I've got the L67 tuning figured out pretty well, but I also can't afford to blow up my transmission just yet to I keep it conservative.
While the PCM is hard to tune, its far from impossible. Most of the L67 guys like to bolt on and go, custom tunes were almost unheard of until about a year ago.
The PCM has a fuel trim system, skews a % of fuel in closed loop, nothing unusual. When you go into open loop (power enrichment), it 'locks in' the last know fuel trim, and 99% of the time it stays 'locked'.
So to tune for alky, you wait till the fuel trim locks in before you spray, so the PCM never actually sees the extra fuel. This is easy, because open loop will happen before you get into boost and start spraying. If it doesn't for some reason, you lower the TPS% to activate open loop.
From there, you pull fuel in the power enrichment tables and replace it with methanol. Its not automated like some of you guy's piggy backs, but you keep an eye on the A/F ratio and tweak it alot. Its not too difficult, really no different then trying to tune your A/F ratio from the PCM alone except you can adjust it on the fly with the progressive controller.
Spraying before the blower also increases the volumetric efficiency a good amount, which is a huge benefit with a roots blower, but if you spray too much there is noticeable bog. *I think* when you try to shove a bunch of liquid through the rotors, the drag/friction required to turn them increases exponentially, so parasitic loss goes way up. Imagine trying to use a roots blower as a water pump, not gonna happen. I think this is also one reason that L67's haven't had much success, people just didn't know what they were doing.
I am looking into using a small nozzle in front of the blower to get the increased efficiency and slight cooling, and then use one or two (depends if I think I can get even distribuiton to all cylinders) below the blower for the majority of cooling and octane.