I believe Peter found that a 50/50 ratio (by weight, not volume) of Distilled Water and Methanol is the best injectant.

I think it's been proven time and again (by idiots who don't realize what they're doing) that if you want to go away from that ratio than it would be better to increase the percentage of water (all the way to 100% water) as opposed to increasing the percentage of methanol or alcohol.

The big thing though, if you have a vehicle tuned with a certain mixture percentage, than it is very important that you maintain that same percentage. I.E ~ Don't have your car tuned with 50/50, then randomly top up with 100% water or 100% methanol. Whatever you map (tune) with, you should drive around with.

Just my $.02