CathInfo.com

Holy Ghost guides the Papacy and the Church overall, substantially, and from the "big picture" perspective.  This does not preclude various detail that would later be subject to reform.  There's a difference between mistakes about details here or there and substantial corruption of doctrine and public worship, where they become downright harmful to souls, the former being possible, the latter impossible.

Unfortunately, some of the dogmatic SVs err on this point and over-extend infallibility in the strict sense to every detail (and some have even gone as far as to claim that anything that bears an imprimatur is effectively infallible and requires internal assent).  On the other side, you have the R&R like this crew who think it's entirely possible for the Church to become substantially corrupt in her teaching and her public worship.  Both of these extremes are incorrect, and they keep pushing each other to the further opposite extreme, as often happens when the balance is lost.

Msgr. Fenton describes the proper balance between the two (see in particular the last paragraph, which I highlight in bold):

Despite the comparative inadequacy of the treatment they give to the papal encyclicals, however, all the theological works dealing with this subject make it perfectly clear that all Catholics are bound seriously in conscience to accept the teaching contained in these docuмents with a true internal religious assent. It is the common teaching of the theologians who have written on this subject that the internal assent due to a great number of the doctrines proposed in the papal encyclicals is something distinct from and inferior to both the act of divine Catholic faith and the act most frequently designated as fides ecclesiastica. Most theologians hold that, while there is nothing to prevent an infallible definition of truth contained in or connected with the deposit of revelation in papal encyclicals, and while de facto it is quite probable that at least some infallible pronouncements have been made in this way, the Holy Father has not chosen to use the complete plenitude of his apostolic doctrinal authority in presenting most of the truths contained in his encyclical letters. Nevertheless they all insist that even in this portion of his ordinary magisterium the Holy Father has the right to demand, and actually has demanded, a definite and unswerving internal assent to his teaching from all Catholics.
...
It might be definitely understood, however, that the Catholic’s duty to accept the teachings conveyed in the encyclicals even when the Holy Father does not propose such teachings as a part of his infallible magisterium is not based merely upon the dicta of the theologians. The authority which imposes this obligation is that of the Roman Pontiff himself. To the Holy Father’s responsibility of caring for the sheep of Christ’s fold, there corresponds, on the part of the Church’s membership, the basic obligation of following his directions, in doctrinal as well as disciplinary matters. In this field, God has given the Holy Father a kind of infallibility distinct from the charism of doctrinal infallibility in the strict sense. He has so constructed and ordered the Church that those who follow the directives given to the entire kingdom of God on earth will never be brought into the position of ruining themselves spiritually through this obedience. Our Lord dwells within His Church in such a way that those who obey disciplinary and doctrinal directives of this society can never find themselves displeasing God through their adherence to the teachings and the commands given to the universal Church militant. Hence there can be no valid reason to discountenance even the non-infallible teaching authority of Christ’s vicar on earth.
...
It is, of course, possible that the Church might come to modify its stand on some detail of teaching presented as non-infallible matter in a papal encyclical. The nature of the auctoritas providentiae doctrinalis within the Church is such, however, that this fallibility extends to questions of relatively minute detail or of particular application. The body of doctrine on the rights and duties of labor, on the Church and State, or on any other subject treated extensively in a series of papal letters directed to and normative for the entire Church militant could not be radically or completely erroneous. The infallible security Christ wills that His disciples should enjoy within His Church is utterly incompatible with such a possibility.

Hey, Lad, while I see +Fenton's point (to a degree) he has as much authority as Fr Wathen or Fr Hesse (a canon lawyer), whom you brush aside as not part of the magisterium.  If you're going to be consistent, then don't hold up +Fenton as some inerrant authority.  His opinion is not gospel.

The Point - May 1953

"...Of these doctrinal dictators, the three outstanding are Father Francis J. Connell, C. Ss. R., Monsignor Joseph C. Fenton, and Monsignor Matthew Smith. These three priests have emerged from nowhere to set themselves up as the official and unquestioned American theologians. Not even the Pope is able to speak to American Catholics without their mediation. His pronouncements require their interpretations, which infallibly follow, in order to make them clear and to show what he was really trying to say.

The opinions and interpretations of Fathers Connell, Fenton, and Smith are disseminated by means of one journal, one university, and many newspapers. These are, respectively, The American Ecclesiastical Review, of which Fenton is the editor and Connell the associate editor; the Catholic University of America, at which Fenton was, and Connell is, Dean of the School of Theology; and the newspapers that print articles issued by the National Catholic Welfare Conference, of which Connell is the star performer, together with the Denver Register, of which Smith is the editor and featured columnist.

Properly speaking, Monsignor Smith is not a professional theologian at all, but only a journalist with a flair for theological dabbling. Connell and Fenton are really the original thinkers, issuing their proclamations from the nation’s capital. Smith is merely their parrot, the voice out of the West. His job is to see to it, by means of his newspaper, that American Catholics are informed of the opinions Connell and Fenton have decided they ought to have. However, he does his job so faithfully and so well — besides which he often adds bright touches and anecdotes of his own — that he deserves to rank with the other two.

Father Connell specializes in giving the “Catholic position” on the latest newspaper headlines. There is not a single curiosity or scandal that he fails to notice and to comment on for the edification of American Catholics. Typical of his unholy interests and faithless comments is the article he wrote last year during the “flying saucer” ruckus. Asking himself the question, how could men on other planets be redeemed, he casually elaborated a scheme of multiple Incarnations and reincarnations of the Persons of the Blessed Trinity, a scheme which turns Our Lady from Virgo Singularis into just one of the mothers of one of the Divine Persons who became man.

Monsignor Fenton likes to make it appear that he is terribly strong and intransigent on the matter of dogma, and that he is persecuted on account of this by those with more liberal ideas. However, as is plainly evident to any long-term reader of Fenton’s Ecclesiastical Review, there is no lasting difference between him and the liberals; he merely says what they say two years later.

In his interpretations of the doctrine “no salvation outside the Church,” his prize interpretations, Fenton lays down conditions for non-Catholic salvation that are so rigid and far-fetched that practically no one can meet them. (This is to show his “terrible strength.”) However, it does not bother him that those who want to go all out for getting non-Catholics into Heaven, do so using his reasons and his authority. All the liberals need is one little loophole, which Fenton gives. Through that loophole, the liberals are able, in their need, to squeeze every Protestant and Jew in America.

The Faith is meant to be something clear and simple, which the Holy Father can teach us in innocent terms, and every man can and must know for his salvation and his happiness. But as long as Fathers Fenton, Connell and Smith are running the show, the Faith is going to be presented as something obscure and esoteric — something that can be known by no one but these priests, and those to whom it shall please them to reveal it.

BY FATHER FEENEY"