Well... my system is still under my desk
I was experimenting with gasoline fuel injectors, but that didn't work, and the project is on hold since then.
A friend of mine uses a progressive kit and 2gph nozzle on a GT (he also tried 3gph but that didn't give any noticeable advantage in cooling, EGTs went a bit down, but IATs were practically the same). His system is switched by boost pressure. We were able to squeeze out additional 15HP from his engine, after W/M and a new remap. Without a remap and with W/M 30% mix the difference was under 5HP. But AFAIK he only uses water now, no methanol.
I will do the same on my car (mostly because of good effect on intake cleaning...) only I will inject proportional to air intake, not boost.