Wires are a good way test.
If it's just off idle that you have your problem, a new power valve probably won't help, nor will a different pump cam (this is only from my experience: your results may vary). :)
Your experience is backed by physics. See
post here for link to video. The main jets are usually much larger than the IFRs so have little effect on flow. This assumes a submerged IFR. A good modification to start with if its high. See
http://racingfuelsystems.myfunforum.org/viewtopic.php?f=25&t=1338
Not enough info yet to decide whether to change the IFR or the IAB. Yes, with 4 corner idle the fine trim screws might only be 3/4 out.
First you should make sure (idle circuit) needs to be richer by doing the super slow opening test I described earlier. If it doesn't need it, then its just extra fuel washing things down..
If it does need to be richer in some of the range, you will then have to experiment with IAB and IFR combinations. Does it need to be just richer or also carry higher into the rpm range? Changing the combo will effect both richness and when it stops flowing.
Keep noting the turns out of the idle mix screws. It's another clue as to what is going on with each change.
