RE: Platt FW-190
Ampeater, yes, 15lb is very light - mine weighs in at around 21lb and like you worked pretty hard to keep tail feather weight down but then went and added a scale tail gear from Sierra - shaved 2oz in the tail by using a foam T/Wheel but did not bash out the fuselage formers like Dave apparently does. I also weighed the balsa wing sheeting and apart from some lateral weight on one side of the engine compartment to counteract the muffler weight did not have to add any additional weight for lateral balance.
What motor and battery packs will you be using?