different dpths for finish tool in the relief toolpath

Title says it all, I have found running different sized ball noses speeds my milling up about twice as fast, example: 10x10  wood doing a flower or???? I start using a 1/4 inch ball end I end up using a 1/16 ball end, the 1/4 inch right now I adjust my "Z" zero to .300" my touch pad is .375, I go to an 1/8" ball end my "Z" touch is set to .365 the final pass is set to .375 (this is my touch pad) the .010 is just fine for the 1/16" bit. I am wondering if we could have this ability to set this up in the software, would be cool. Right now if I run a roughing pass with a ball end it takes forever seem sometimes to run longer than the finish pass.

   All these adjustment in the finish pass, to set the "Z" off the top of the material.

    mike