Sometimes all a kit is useful to me for, is the planes' outline. The parts themselves are good for use as templates, so lighter wood and or deletion of the part [like ply doublers, triplers, spruce spars, oversized pieces, full sheeting, etc.] can be done. Forget about using 1.5 oz servos, 2 oz RX, 3 oz battery, heavy LG and wheels, and last but not least, a heavy .40 that weighs a pound, there are light weight .40s out there that weigh 3 ozs less and can generate 6 pounds of thrust with a 10x5 prop. It is a bunch of little things that add up to a light model. A good way to learn light techniques is to get into 1/2A or small electric building, then apply what you've learned to the bigger stuff. Another way is to learn how .60 sized pattern planes are built, these techniques down size nicely into .40 sized models.

The aerodynamic fixes to an overweight models' problems don't have much power at typical approach speeds. At 15 to 20 mph, a 5 inch chord wingtip, with this much weight heaped on it, and no matter how much hocus pocus is thrown at it, is just going along for the ride.