Sound like an idle check issue, Rons set's theirs up pretty low in the PSI range, mainly for just making it easier to get fired. Any Toilet or Terminator I set up gets converted over to a Kinsler barrel valve with an external idle check.
How sure are you of the finish line pressure? If it's on a tattle-tale gauge that comes off the pump or barrel valve it's going to be spike pressure and not finish line pressure. Reading at the nozzle is best.
An educated guess would put fuel pressure at 7000RPM closer to 100PSI.
Nobody else makes the rons style drop in jets. You could change the nozzle bodies over to enderle and just use their nozzles. Cheaper and much easier to source.