Yes, the Gremlin is legal. It can be flown in Open B class with any engine .30 or smaller.

However, the Gremlin is a fairly small plane, and it can't turn with the top B class planes. For club stuff though, it's fine.

I just hit Yahoo Maps to see where Big Flats is. You don't look very far from Endicott, NY or Montrose, PA, both of which have held contests in the past. So you'd want planes that you could fly at one or both of those sites.

If you are just flying club combat, and aren't going going to follow RCCA rules for now, I suggest you require stock mufflers. That will keep speeds down at least a little bit. Mousse cans add a lot of power, and a light Gremlin on mousse can can be a real screamer, which isn't necessarily a good thing.

This year, we flew SSC class in Endicot, and there is a group in the Rochester area that flys SSC on a regular basis, though they don't sanction or publicise their contests. So you might want to at least take a quick look at SSC.

There's also been a lot of talk about slowing down B class by requireing stock mufflers and using a spec prop, usually something like a 10x3 or 10x4. That slows things down and reduces impact damage as well, which is often a good idea for club combat.

On the other hand, if you do want to go with RCCA rules, and you decide to sanction a contest, let me know, I'll make sure it gets at least a little publicity, and I might even show up. (which may or may not be a good thing )