I believe all the CMRI chapels do.

Quote from: Pyrrhos

Quote from: Sigismund

I believe all the CMRI chapels do.

This is not correct, in fact they are the only major sedevacantist group which uses the so called 1955 Missal.

Do you have verification of this that you can share? Is that info on their website?

I was wondering which other chapels use the St. Pius X Missal besides those of St. Gertrude the Great in Ohio, the SSPV, St. Athanasius in Vienna, Virginia, and Our Lady Help of Christians in Garden Grove, California.

under the authority of Pope
Pius XII, who was not physically well and only had 4 more years to live.

What's wrong with doing so? Msgr. Gromier heavily lambasted the 1955 Holy Week reforms.

The Pope praised the Holy Week rites, because he totally trusted Msgr. Augustino Bea and Fr. Bugnini in reforming it.

"And how should one love the Pope? Not merely by word nor tongue, but works and integrity. When one is loved, all of that person’s thoughts, wills, and desires are sought out for assent...to demonstrate our love to the Pope it is necessary to obey him...when we love the Pope, we do not dispute whether he commands or requires a thing, or seek to know where the strict obligation of obedience lies, or in what matter we must obey; when we love the Pope we do not say that he has not yet spoken clearly – as if he were required to speak his will in every man's ear, and to utter it not only by word of mouth but in letters and other public docuмents as well. Nor do we cast doubt on his orders, alleging the pretext which comes easily to the man who does not want to obey, that it is not the Pope who is commanding, but some one in his entourage. We do not limit the field in which he can and ought to exercise his authority; we do not oppose to the Pope's authority that of other persons – no matter how learned – who dissent from the Pope. For whatever may be their learning, they are not holy, for where there is holiness there cannot be dissent with the Pope." [allocution of 18 November, 1912, AAS vol. 4 (1912), 693-695. Selection from p. 695]

E come si deve amarlo il Papa? Non verbo neque lingua, sed opere
et veritate. Quando si ama una persona si cerca di uniformarsi in tutto
ai suoi pensieri, di eseguirne i voleri, di interpretarne i desideri. E se
nostro Signor Gesù Cristo diceva di sè: si quis diligit me, sermonem
meum servabit, così per dimostrare il nostro amore al Papa è necessario
ubbidirgli.
Perciò quando si ama il Papa, non si fanno discussioni intorno a
quello che Egli dispone od esige, o fin dove debba giungere l'obbedienza,
ed in quali cose si debba obbedire; quando si ama il Papa, non
si dice che non ha parlato abbastanza chiaro, quasi che Egli fosse obbligato
di ripetere all'orecchio d'ognuno quella volontà chiaramente espressa
tante volte non solo a voce, ma con lettere ed altri pubblici docuмenti;
non si mettono in dubbio i suoi ordini, adducendo il facile pretesto di
chi non vuole ubbidire, che non è il Papa che comanda, ma quelli che
lo circondano; non si limita il campo in cui Egli possa e debba esercitare
la sua autorità; non si antepone alla autorità del Papa quella di
altre persone per quanto dotte che dissentano dal Papa, le quali se
sono, dotte non sono sante, perchè chi è santo non può dissentire
dal Papa.
(allocution of 18 November, 1912, AAS vol. 4 (1912), 693-695. Selection from p. 695)

So we're just to ignore the problems in the "reform", even if it is orthodox? That isn't the spirit of true liturgical reform. I hope the day will come when the liturgical revolution which began in 1951, will be consigned to the scrap heap, where it belongs and true liturgical reform be implemented. As I said previously, your principles would make us go sede, since you say we can't criticize any decision of the Pope, especially the Novus Ordo. There are other things Popes in the past have done that would have make them at least material heretics, and yet sedes have not called them anti-Popes!