I've just upgraded my Taig mill with microproto's new dsls "servo" system which uses Mach 3 as the post processor. The biggest problem I have is with the different speeds of the x,y,z, and 4th axis. When I'm using the 4th axis, the angular motion of the 4th axis is much slower than the movement in the x direction. If I increase the speed, the cutter moves too fast through the material (wax). Is there a way to scale the speed of one axis without affecting the speed of the other axis?

Yup, set the Rad of the part on the Settings page