RCpilet, 32:1 is fine. The differences between 25:1, 32:1 and 40:1 are really only about 1 Oz - roughly 5, 4, and 3 Oz. per gallon respectively. I usually just eyeball it and err on the plus side for brand new engines, but it isn't really that critical unless you start pushing the limit with the 100:1 stuff.