My kids have 2 strokes and require 32:1 oil to gas mixture. My questions are, if i premix a 5 gallon jug for both bikes, how long is it good for. Or is it better to mix in a 2 gallon container to use immediatly? The reason i want to use a 5 gallon mixed at 32:1, is so that i would not have to use so many gas containers. Any ideas? Thanks..