MSD

You are running to much total timing.I have a 416 500hp 570 ft lbs of torque with a custom camshaft.Total timing 36 runs and idles great.
I think you should set the timing like i said or the way cracked backed suggestion which i have also used and leave it alone and start looking elsewhere for your problem.I put a 2 brand 650 holley double pumpers on mine and the idle acted like your are describing.Ended up with a 670 holley with no more problems.Looking back the pcv system was affecting my idle circuit