Yeah I got the mod done.. it's actually quite easy.
I've got both magnets centered within about 5%.. probably closer than that even... good enough for a calibration to fix the rest.
I used 'windshield sealer' which will hold very well once it cures, so my biggest problem was holding the magnets in place while that happened (they kept wanting to shift towards that small screw right above). I cured that with a very thin strip of that cushioned double-sided tape just under that screw. It positioned the magnet perfectly below the sensor, and only a slight left-right adjustment was necessary to get it centered.
After letting it cure all afternoon I once again tested it and both axes are very very close to being centered. I haven't actually had a chance to use it yet though.
