ive got a 5 gph nozzle too. i have windshield washer fluid in it right now but i got a gallon of straight meth im pouring in once the washer fluid is gone.

the reason they have to suggest a 50/50 is because they cant legally tell you to run an explosive/flammable mixture. over 50/50 is now flammable, but the only way to really make use of it is to run 100%.