Puckish: I don't think using a guide is cheating at all. It wouldn't be if you'd read and memorize it, so why not have a look at one from time to time? I think cheating starts where guides aren't capable of covering the complexity of situations, and where you have to make different calculations for individual situations - and use software for that, because it exceeds your own capablities. Every information which fits on a piece of paper is legally usable, I'd say. But I don't know ;-)