64-bit JIT FPU being broken wasn't surprising. This code hasn't been checked for 64-bit compatibility yet. So in future commits, comfpu option will default to 0 for 64-bit versions.
Regarding the 32-bit JTI FPU and the font rendering - does "future version" behave worse than the current development version? Or is the behavior the same?
Regarding accuracy, an important point is that there's completely different code involved with interpreter FPU emulation and JIT FPU emulation. I don't know if the JIT FPU is supposed to have the same accuracy. But there is an additional option, you can try
(uae_fpu_strict = 0 means "faster, but less strict rounding" according to source code).