Hi Julio,
I would agree that increasing alcohol as the boost increases is definitely the way to go. I've been using the SMC Progressive Controller which I like a lot better than their standard controller. Seems to make the boost come in faster.
The reason I decided to put in more alcohol at higher RPM is that I figured as the RPM increases and the engine cycle time decreases(intake stroke lasts a shorter amount of time) if you're always spraying the same amount of alcohol(once you've hit max boost), as the engine spins faster you have less alcohol going into the cylinder.
I was planning to run a second stage anyway, and by triggering it off RPM, I was trying to keep the amount of alcohol going into the cylinder more constant as the RPMs increase.
Maybe a dumb idea, but I know from using Nitrous on a number of cars, if you trigger a 250HP shot at 3000 RPM the engine goes crazy, whereas the same 250HP shot triggered at 5000 RPM has much less effect cause you just can't get as much NOS in the cylinder when the engine is spinning fast and the intake stroke doesn't last very long.
Right now my car is so poorly tuned(the O2s in direct scan are at a 45* angle) that I'm in no position to tell anyone what to do, I just figured I'd give this a try cause it made sense to me and if it saved me from having to shell out for injectors again that was a bonus.