I pretty much throw out the reccomended mfg. specs on the proper COG, rarely are they dead on, with at least the kits and arf's I've assembled in the past. I'd say, toss your's a bit forward, see what happens, and you are getting the same results, then go the opposite direction, there could be something happening with your initial build that requires a different COG in the first place. You may have to add some weight to the nose to achieve proper results.