900 isnt too bad, although i like 1000-1050 at the solenoid (pressure from the bottle to the solenoid drops esp. through a #4 line).
Fuel pressure is probably in the mid 40's or so.. ? Im not sure how much Fuel pressure we have at WOT in our cars. Like David said, try out a .024 fuel jet, and jack the bottle pressure up a bit more and see what happens. Would like to see how the timing is ramping while on the spray.. im sure ya dont have that option though..?
btw.. is it going rich throughout the entire run on the spray, or only toward the end?