I too have had no problems with running the antenna down carbon tubes (is it Carbon or just black fibers?). I make sure the tube length is NOT any fraction of the antenna that can be divided by 8 and is less that one wave length long. There is also a concern about reflective elements but with our small planes this is not much of a problem.
I like the folded battery idea. Can the battery come out the front for battery changes? I did not go this route as I use the same battery packs for my Speed 400 racers.
A note about setting up my V tails. On my "Simply The Best" 1.5m 2 channel V tail HLG I use a very aft CofG. I offset the sevro arm so that durring a turn the servo arm rotation would gives me more down than up. This gives me an little automatic down in a tun to keep from stalling because of loss of air speed due to drag at the start of the turn. With these very light ships any induced drag at max coefficient of lift manuvers (thermaling) can slow the ship into a stall. With rudder elevator ships and a rearward CofG this is a real problem. One could mix this into the TX, As a plus I need less forward stick to fly inverted
This drag induced stalling is why some times you hear someone say that upping the wing loading helped the plane turn. The extra weight gives inertia to over come the drage induced by yawing the plane into the turn.