Your comment that the hole pattern was different made me re-examine my blades.
Oh dear. Even within MK and Wilson blades (I think I threw away my old MK Dance and Wilson Coronation Ace blades , but I still have some old MK Club 2000 and Wilson Excel blades - though both are pretty old, so things may have changed, and I can't use their rocker profiles), the approximate positions of the sliding and 2 of the round holes are interchanged, and the hole spacing is not the same. On top of that, my MK and Wilson blades have rounded mounting plates (assuming that isn't a consequence of boot mounting), whereas my Ultima Matrix I Mounting plates are flat (though the front and rear plates are not co-planar).
It looks increasingly hard to compare blade shapes in a consistent manner. Clearly hole positions are too hard to correlate.
I think your idea of overlaying the toe picks is pretty good, though maybe that works well because neither of the blades you are using is meant for beginners, and both have almost exactly the same rocker profiles relative to those toe picks.
I'm fascinated that (your) Wilson Coronation Ace and Jackson Ultima Synchro blades are so similar in rocker profile. Of course, maybe your blades aren't new. Maybe your skate tech the profiles to be similar, as many skate techs do? (But I noticed earlier that my Ultima Matrix I runners for Dance, Synchro, and Supreme (freestyle) profiles were essentially identical, except for toe pick teeth and tail length.)
If I hold my printed rocker profiles against my blades, I can fairly easily fit the blade against the right radius profile. I can do that with both the main rocker (8' for my Ultima Supreme and Ultima Dance blades), and the spin rocker (about 1' for same). I suppose I could pick out precisely where they intercept (the sweet spot) if I printed the profiles on transparency material - but ink-jet-compatible transparency material packs are fairly expensive. I guess one way to do this is in software, after scanning the bottom of the blade into an image.
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I'm guessing, Bill_S, that you only have 10.5" blades, so it isn't easy for you to figure out how blade shapes vary with length.