I've ran stuff compiled for 020-060 with no problems at all on OS4. The user mode of these chips varies very little. It's only when an application directly uses some specific (usually supervisor mode) function of a processor (such as MMU or direct cache manipulation) you get problems.
In the best intrests of compatibility, since the interpretive emulator emulates 68020 + FPU I'd be inclined to use either 68020+FPU or generic 68020-68060+FPU (the latter doesnt have any FPU instructions the 040/060 can't directly manage) binaries first. It's most unlikely that there would be any noticable speed gains from an 060 optimised binary over an 020 one when dealing with emulation anyway.
