Why don't you call Jim and get a cam from him? The ONLY way to know where the rpm range will land with a "given" duration number is to run a cam or two with your exact induction set-up, and bore and stroke, and get some idea of where it will shake out. Bore, stroke, engine size, throat diameter, valve size, port and manifold cross-section, runner length, and plenum volume......and a few more things I won't go into, will all move where the peaks occur, and how far apart they will be. You also need to think about some of the lower lift points, and throw the .8, .9, and 1-inch lift numbers out the window, as long as they don't back up after .750.....
Jim is a pretty smart cookie, and I would wager that he knows what the heads like, if he has worked with them on engines in the past. JMO.
If you plan to consider the flow from .500-up only, you will need at least a 4.5 bore, 3.5-ish stroke, short/fat intake runners, and a tach that goes to 12000.