I got it working 2 years ago doing the same thing
Wildfire problem is that part of the program is 68k. If you use PPC operators you end up with race/synchro problems which make the interface crashing.
I don't think that it would take much effort for the Wildfire author to do a native version but unfortunately he is not updating it anymore.
Sad thing that such a good app and other such as Tornado3D were abandonned
If you want to see Wildfire benches go
here and scroll down up to the table.
JIT gives you about 50% of native PPC speed but it is still about 7 times faster than a 68060@50 on a G3 600.
[ Edited by cdfr on 2005/3/9 23:26 ]