I have found that my car likes injector phasing to fire at the back of the closed valve just before it opens, instead of firing as it opens.

It's a difference you can feel.

I am using off the shelf Mustang GT-500 injectors, @ $24 a piece. The spray pattern is setup for a dual valve design, but they work better than my old non-split injectors I had in it.

My duty cycle is 65% at WOT, on a car with 500 HP, and 542 Ft-Lbs.