I have one with a Moki 1.80. With the gasser I'd put the tank on the CG. It's not really possible since the servo tray is in the way but put it as far back as possible until it hits the servo tray. That's where mine is. It will fly much better (trims won't change). Other than that keep it light. Use a CF spinner if possible. Any way you can lighten it up would be a plus. With a Moki 1.80 it's 14 pounds. With that engine more like 14.5 pounds. There was a review with that engine a year or so ago. The weight came out at 14.7 pounds I think. It's a very nice flying ARF. Not much coupling in knife edge. Does any 3D manuever I've tried. It's only flaw is its weight. Use a 16 oz tank to keep your wet weight down. Those engines burn very little fuel compared to glow.

PS: If you have experience lightening air frames, that would be a good thing to do. Got a Dremmel?