balsa,

just a suggestion: use 2 Rx batteries for your airplane. A week point in any battery system is the switch, especially in any glow or gas powered model, so any model in which I have more than $500 invested, I use two Rx batteries, each with it's own, heavy duty switch, to power my Rx. In larger models, those batteries feed a "power expander", etc. so that the servos get full power while the Rx is fed power at the proper voltage without any loss due to amperage drain from the servos under load.

Two 6v, 1500mah NiMh batteries feeding your Rx is not a lot of weight for a .61 size model and provides redundancy and greater capacity, which equals peace of mind!