Ag-la7200 loses 0.1 f, and is excellent with wide lens for me panasonic pancake 20 f 1.7 is the best.
I have the 50 f1.8 and the 28 f2.8 zuico OM and work well.
So I think will go well with canon FD.
does not work with medium telephoto and telephoto, over 60mm.
also may depend on the construction geometry of the lens,
example: does not work with sigma 30 f1.4
Try it
Max