Digger did I see your going to use two receivers and just one battery pack or did I miss sumpin here.
You can save weight going with lipoly or lithium but the expense is another deal .
I just used a single receiver and battery pack ,Used the 7 servo rule 7 or less = 1 receiver and so far it has been a flawless setup.
One thing I may do is move my tank back to the CG later on I liked the way you did yours and may copy your idea *S*
Outside of the gear and tires I don't know where you can shave off much weight ,make the openings in the structure larger I suppose then risk a failure maybe ?????
I will say this ,My plane flies great at 16.25 lbs dry weight and I pick up approx 1-1/2 lbs of fuel dosen't seem to effect it what so ever .Like you I was very hard core about going over a certain amount of weight. I need to get more flying on the plane and decide if I can add a smoker or not .that could be the straw ya know .anyway good to see your still at it i'll check back later on to see how things are coming