isn't it proven by jeff at modern that his cnc program on 906 heads outperformed a hand porter on a FAST build getting a 440-6 RR into the 10 second zone while the hand porter was only able to get the A12 RR to low 11's.
i believe thats proof enough that CNC'ing one of these heads works better then hand porting.
if i were to do it again CNC'ing is my choice,hands down.