Personally I'd stick to os3.1 for an '030. There's no real advantage in using 3.5 or 3.9 anyway apart from less work to build up a nice system. OS3.9 is significantly slower, to a point that it's really only an option for '060 users, and even then I wouldnt use it. I do like OS3.9, but apart from Amithlon or variants of x86 UAE (ie. jit cpu emulation) it's just too slow (for no apparent reason). This isnt to say it's unusable, but when resources are limited like they are on 680x0 machines it simply eats into resources too much. OS3.5 is somewhere inbetween.
