I'm confused. If you're talking bridge spacing, they're the same... 19mm (unless your 535 has custom spacing). If you're talking nut, you can order a narrower nut as a standard option.
+1 I believe the bridge and nut spacing is the same between the two basses. Interestingly, I'm not up to speed on the 4 strings, but isn't the Sadowsky 4 string spacing even wider than the standard Fender 4 string spacing? I seem to remember 20mm (could be wrong there)
Something strange here. Might just be talking about the neck profile, which flattens a bit more above the 12th fret (as does the radius) on the MTD.... pretty minor though.

