swapping 700R4 for a SM465-now I'm confused!

[72C10chevy4x4]

I'm finding a lot of problems (and they're expensive to fix) and now I'm confused. after talking with Novac(k) it sounds as if the 'regular' 4x4 output trans shaft which needs to be installed, may be too long?? I know there is an adapter between the tranny and transfer case-how does the tranny output shaft and the input for the tranfer case actually meet? is the meeting inside the 3.5" adapter plate? Has anyone taken their 10 spline (sm465) transfer case input shaft out and swapped in the 27 spline (if so-how difficult??)?

if anyone has a tranny/TC adapter and/or a 205 transfer case which was originally connected to an auto tranny, for sale-let me know!

is there any benefit to a 10 spline vs a 27 spline input/output shafts?

thanks,
Paul