Here's where Father Chazal first articulated his position:
1) agrees with SVs that Bergoglio (presumably his predecessors as well) is a manifest heretic, without doubt
2) says that on account of heresy, they are "impounded" due to being vitandus ... "to be avoided"
3) as a result, they have no authority, and are in a state where they are awaiting form delcaration of loss of office by the Church
Early on, he actually mentions the crucial distinction also made by sedeprivationists, that God confers the authority directly, but that the Church designates the man to hold the office.
This differs from classic R&R (and actually does most closely reflect the position of Archbishop Lefebvre) in that he states these men lack all authority, whereas classic R&R holds that they do have authority, but can be disobeyed on a case-by-case basis. He states that they must be categorically ignored and that they have no authority whatsoever. So, for instance, he cites the case of Padre Pio (where he presumably agrees that he was a saint), but that he rejects the canonization of Padre Pio, not accepting him as "St." formally, because not even the "correct" actions or teachings of the Concilair Popes are acceptable. Father Chazal, therefore, doesn't have the problem of needing to accept St. Montini or St. Wojtyla either.