help with tuning an AED 750 Ho

Try a .031-.032 primary IFR. With 3.23's, you should still be on the transition slot so the IFR is where I would concentrate time and effort. You will need to readjust the mixture screws.

What is initial timing? Should be up close to 20* with a XS282s camshaft. Might need a bushing that limits advance to less than 18. I have some 10 and 14* bushings available.

I usually never run the two lightest springs in an MSD distributor. Light and medium is what I run most of the time on stuff like this.

Sound like a solid build and should run real strong.