Jetting Recommendations

I've just put individual filters on my '78 GTS and will be making a new airbox or something. The mods I have to the engine are Electromotive HPV-1 DIS, and cats but no muffler (long story). Aft the cats are basically straight pipes with Ansa tips (with resonators). I get some popping on decel, and constant rpm (say 3 or 4k) in neutral, and an occasional one at idle.

I've read that many have just gone with richening up the mains from 125 to 135 (some even 140). Others have said this will be too rich. Unfortunately, I don't have access to a dyno nor an air/fuel meter.

What recommendations does everyone have for my setup? Should I just do the mains, or should I also consider the air correction jets?

Thanks

Henry