if your on the same day, u run out of 20, throw some 30 in it, i would richen then tune again for performance. Everytime i change nitro or something i richen it a bit and start again, tune for performancee, when i get to where i like it i temp it to make sure its not like 350 faren lol and for reference and run it like that.

Take top fuel dragsters for instance, they run nitromethane and they get rebuilt after everyrace thats high performance fuel.