If you do some lightening you can get UNDER 9lbs. with a big glow. For example I run the ST 1.40 and my plane weighs about 8lbs. 10 oz. I use a Mezjlik CF 18X6, Graphtech LG, Futaba S3305 servos, Small Futaba 6V battery, 12 oz. main tank with 2 oz. header tank, Bisson Pitts Muffler, Stock Engine Mounts.

If you run the stock mounts, The heat from your engine will transfer into them so they function as extra cooling "fins." <<Little Tip I picked up from a friend.

Back to the original question- Yes use the inboard aileron bays.