I agree that this has always been a somewhat cumbersome part of dealing with the mix windows, when you change to keystone mix or curve mix, you get a square area to deal with, so I always end up with .74 or .76 for aspect and about 9.58 for scale to make it 16:9 and somewhat close to the same size as using say flat locked to corners, which seems rather arbitrary to me, I can't figure out why the numbers wouldn't be nice and ? Then I can't type these values in again anywhere else, or save them in case you accidentally hit reset geometry... Curve mix is even more interesting as there isn't even a value for zoom, you just kinda eyeball it.

I haven't really played with mad mapper too much, but I have played with exact map a little bit and it is also not what I would call quick and easy since you have to type in some numbers, and drag around corners for others. No matter what it seems to take a while.