Fly what the locals fly and get in some stick time. Maybe you could get one from another club member. I have two os fx .46 that I will not use in combat because they cost too much and weigh too much to fly in sanctioned meets. If that's what your guys are flying, see if you can get a used one to sacrifice. A nearby club had an unsanctioned meet last fall flying with engines up to .47 A few of the contest circuit guys went and cleaned up flying os fx .25 engines with mousse can mufflers. If your .46 has some age on it and you're willing to risk damage, go ahead and use what you have.