24 Pound injetors and FP..what's myth what's fact?

Well doing a little self tuning tonight and curious about a rumour I had heard that 24 pound injectors and get a little cranky under 40PSI FP. Now presently running 14* and 42PSI...with that the car is running nicely, but I feel there is a bit more to be had. I'll be pushing the timing up just a tad to 16 but like to drop the FP closer to the stock 38-39 range to see if I can lean her up a bit at WOT. I'm getting black discharge when dropping the hammer confirmed by a buddy trailing me..not to mention she is eye watering at warm idle. I'm quite aware that the puter will adapt FP at idle and part throttle but my concearn is WOT. What I've heard is the 24's fail to atomize fuel properly under 40PSI and I'm wondering if this is acutally fact or fiction?

That' more along my thinking...I feel though the 42psi is sure safe, I've been thinking stock pressure setting 38-39 would be a happier number for making best power.