I propose no such thing.
Which episcopal seats do you claim the sedevacantist bishops to possess?
I merely propose the only Catholic Bishops remaining have the tacit ascent of the Holy See. I base this upon factual history in which bishops were validly consecrated and had formal Apostolic Succession without the expressed consent of a Pope.
During the earlier times of the Church, the corpus of Canon Law had a different shape than it has today. For example, the Pope often provided jurisdiction explicitly through the Sacred Canons to cathedral chapters to elect their Bishops, and these elections then had to be approved by the Roman Pontiff. That is essentially different from creating a kind of 'tacit approval', based on a new and heretical notion on Apostolic Succession (the pretension that Apostolic Succession can exist without the possession of an episcopal see), while invoking an imaginary vacancy of the Apostolic See. The concept of "independent bishops" is a novelty, and such bishops can never be Apostolic Successors, because all jurisdiction flows from the Roman Pontiff as its origin.
I have created nothing. They come from the line of Thuc, Lefebvre and two others and it did not matter if these valid successors were SV in 1959, 60, 61 so long as they were Catholic. Do you propose the Lefebvre was not Catholic?
Archbishops Lefebvre and Thuc both recognised the Pope as Pope in 1960. Where were your sedevacantist bishops during that year? It is a simple question, and the answer is equally simple: They did not exist. Remember, when all the bishops (and vagus bishops consecrated outside of the papal jurisdiction are no formal bishops) recognise a man as the Pope of Rome, then his validity is a proven fact. A dogmatic fact.
Francis is the Pope of Rome, and it is objectively a schismatical act to separate from his jurisdiction.