I cant answer your question for you, but I know if I were to convert a MKII to a 7M and auto combo, I would figure out SOMEWAY to put the bigger tranny in the car. Even if nothing but piece of mind. I don't like doing a job twice, and that's one of the things that's held me up with all my Supra building. Wantign to plan out the perfect combinations so that I dont HAVE to go back in later and go, "oh well,.. this tranny tore up, guess I'll have to put another one in". Or, "yep, too much power for this clutch, guess I'll tear it apart so I can change it with something else I should have put in there in the firast place" I dont knwo if that helps you any, but that's just my two cents wroth.. 
Scotty
Scotty