Hi Trad123, I believe I gave it earlier. Anyway, this is the portion, with the essential form specified by Pope Ven. Pius XII in red. "
Prayer of Consecration of a Bishop in the Old: "THE CONSECRATION OF A BISHOP - It is truly worthy and just, right and profitable unto salvation that we should at all times and in all places give thanks unto Thee, O holy Lord, Father Almighty, Eternal God, honor of all dignities which serve unto Thy glory in sacred orders. To Thee O God, who, in the secret communings of familiar intercourse, giving instruction unto Moses Thy servant, concerning, among other branches of divine worship, the nature of sacerdotal vesture, didst order that Aaron, Thy chosen one, should be clad in mystic robes during the sacred functions, so that succeeding generations might be enlightened by the examples of their predecessors, lest the knowledge derived from Thy instruction should be wanting in any age. Since, in deed, with the ancients, the very appearance of symbols would obtain reverence, and with us there would be the experience of the things themselves more certain than the mysteries of figures. For the adornment of our minds fulfils what was expressed by the outward vesture of that ancient priesthood, and now brightness of souls rather than splendor of raiment commends the pontifical glory unto us. Because even those things which then were sightly unto the eyes of the flesh, demanded rather that the eyes of the spirit should understand the things they signified. And therefore we beseech Thee, O Lord, give bountifully this grace to this Thy servant, whom Thou hast chosen to the ministry of the Supreme Priesthood, so that what things soever those vestments signify by the refulgence of gold, the splendor of jewels, and the variety of diversified works, these may shine forth in his character and his actions. Fill up in Thy Priest the perfection of Thy ministry and sanctify with the dew of Thy heavenly ointment this Thy servant decked out with the or naments of all beauty." See: https://archive.org/details/consecrationbish00unknuoft Supreme Priesthood, Perfection of Thy Ministry etc etc are all references to the High Priesthood or Episcopacy. Also note the examples of the invocation of Moses and Aaron etc who were High Priests under the old law and this same Grace is invoked in the Consecration. The entire prayer of Consecration is always important to take into account, since it pertains to integrity; no doubt the essential form confers validity.
It must invoke the grace of the Holy Ghost and it must make clear the power of the specific order being received.
Ok.Fr. Cekada would agree that Spiritus principalis could signify the grace of the Holy Ghost. But where is the term indicating the power of order?
Ok, Spiritus Principalis is taken as signifying the Grace of the Holy Ghost. What specifies the Power of the Episcopacy here, then? The continuing portion of the essential form itself that says "The Spirit given by Him to His Holy Apostles". It seems clear the Apostles were Bishops, therefore an invocation of the Spirit given to the Apostles can hardly refer to anything other than the Episcopacy.
Priests in the mainstream Church like RomanTheo should make the right decision to start offering the Tridentine Mass, and receive conditional ordination, if a Traditional Catholic Bishop, after judging all the specifics of the situation, were to recommend doing so.