I agree to run C16. You can do the regulator crush on it to give it a starting static pressure to say around 55psi. It takes a few tries to get it right which means pulling it in and out....a real PITA. You have to do it incrementally or else you will have a FUBAR'd reg.
You basically use a correct size socket which I don't recall what size then tap the top of the reg with the socket and small hammer. Tap it not hammer it. This will crush the diaphram essentially providing more pressure. Very small tries until you reach the psi you need/want. Keep in mind, pressure helps and is sort of a band-aid IMHO but for the long term, a larger injector would be better and more consistent at more reliable lower duty cycles. This was popular in the 80s when the Mustang EFI came out and there were no supporting mods to be utilized yet.
A lot of work to keep everything stock like, so you could gut the internal pump and reg out of the tank and using an external pump and aftermarket external reg to do fine tuning. Usually that is best for Turbo and big Nitrous setups. Again, eventually you'll want more so now is the time to get bigger injectors and tune it via ECU
