I have one manual housing here and I can make it work.
What I am doing at this time

The AY6 gearbox has an integral bellhousing that I will be cutting off. This leaves me with a row of perimeter fasteners to work with. The AY6 had a 9" depth within the bell that I need to shorten a few inches so the finished unit comes out the same length as the AW3 it will be replacing.
What the automatic bell may offer me is that the more open rear section might adapt easier once I can get these all drawn up.
I also can make adapters to the MA5 and AX15 gearboxes and the auto bell should be better for them too.

If what I am working on pans out I will have about 6 different gearboxes to mate behind these engines. This will be for both car and truck use. Most of these will be bolt on, the one I am doing now is more complex.