To the best of my knowledge you want a flat AF curve but heck if I know. You might try posting this question over at Speedtalk or just do a search over there first. It is a topic that comes up a lot over there with the EMC guys.

Another suggestion is to call the tech line at BLP (Bo Laws) Those guys are pretty darn smart carb guys and they'll talk. The guys at Braswell are also darn smart but they usually don't talk, or at least, they don't talk to me!