I'm 99% certain that if a Pro-Systems carb (with F and R idle screws as I presume most are) is correctly sized and calibrated for a motor combo, you shouldn't need anywhere near 2 1/2 turns out on the Idle screw. Check with PAtrick because mine only needs maybe 3/4-7/8 of a turn from bottomed out. He said if it cranks with 1 full turn its In the right range and turn them In until you get a stumble. They are much more sensitive than an oem calibrated Holley.

Cold start (or Especially if it hasn't been cranked in a while) I'll sometimes fatten it up a 1/8 turn and turn the idle screw a full turn for a few minutes, then I back it back down to normal and I'm good for the rest of the day, as said its a price unwilling to pay for a non choke racey motor combo. Once it's warm its 110%