Holley/Demon Carb stumble

I'm going to start with the stock jetting of the Proform main body. I believe, as you guys do, that it will need to go down in jet a lot!!!!
But i'm scared too just drop 4 jet to start with, with all the popping and banging i had before when i did that.

also going to cut up my "removed exhaust system" and see if i can get a colector long enough to get some low speed/idle reading with my o2 meter.