Kodak Ektar 100mm f3.5 (from a Medalist I)

I have a Medalist I that's non functional so I pulled the lens off (the Supermatic only fires at some random speed) so I could fix up the shutter. I was curious whether the cells would fit into the Supermatic No 2 from an Ektar 127mm f4.7 (turns out they do) and whether the spacing would be right (it seems to be). Since the 127 was on a 4x5 board, I stuck it into my 4x5 Speed figuring it would roll off badly outside 2x3 but at least I could see whether it worked okay (lens spacing particularly). Imagine my surprise that an image looks quite nice focused from close to about 75 feet (far as I could get from the comfort of my porch) and, of course, is very bright, and, strangest of all, looks even all the way out to the corners. I realize looks are deceiving and I'll try it tomorrow with film but anyone have any experience with this?

EDIT - I tried it out some more and it does roll off into the corners, particularly focusing out to infinity. Still, might be usable for B&W and a lot of fun on my 2x3 Century once I find a lens board to fit it. How do I correlate the aperture scale (since the shutter starts at 4.7 and the lens is 3.5)?

Thanks,
Dan