Mike, not sure from your write-up exactly what you are trying to accomplish - But, I have not found anything I wanted to do with my Taig mill that I could not accomplish with Mach3 and a free CAD program (CADX11). There are a couple of a surfacing programs in the Wizards function of Mach3.
I have access BobCad, but have not found it to be any more useful than Mac3, Cadx, and DeskEngrave.
Save your big money for more important things like metal and beer!
Bob @ BobsShop - BTW - I am not associated in anyway with any of the above mentioned programs