RE: How to keep weight down. Epoxy or ca
try out locktite 'sumo' glue. its a poly glue like 'gorilla', but it foams 50-60% less, and dries translucent white.
easier to cut away after dried too.
i also only use epoxy(thinned) for fuel proofing, or mixed w/micro ballons for fillets.
i glue 90% of my planes stabs with thin ca, if you have a tight joint it will bond very well.
(a tight butt joint glued with thin ca is stronger than a joint with gaps glued with epoxy/thick ca)