Starting Shift Point

I only have experience with that cam and setup in a 440, and it is out of wind at about 5,600 and falls off fast.

I'd start at 5,500. Make a pass and up the shift point 200RPM each run until you see your time falls off.
I had that cam in my 440 Charger and it wanted shifted at 6200-6300 (4.10 axle, mild ported iron heads, 800 DP, CH4B intake, 9.4 CR, 4260# curb weight.) Anything lower slowed it down. And ET's were flat up to shifting at 6700 rpm. So I shifted at 6200-ish to save the motor.

You nailed - start around 5500 and move rpm up a couple hundred until you find best times. In the perfect world, the shift would drop rpm back to a poont at the exact same power level thus maximizing area under the power curve. But as always, "your results may vary."