Adriaan beat me to it Mike, but I was going to suggest using rechargeables for only the LED supply, and just buy a good quality 9v battery for the instrument preamp. I always buy a two-pack, and keep the extra in my case pocket.
I've had pretty good luck with the Duracell Quantum Series (red-tops) but I suspect the packaging is 95% of a marketing strategy, and plain old copper-tops would be just as fine. For that 5 minutes the backplates of my Alembics are actually open though, they sure look nice... and, well... powerful.
Congratulations & Compliments on that Dragon Wing. That's a fine-looking instrument. Welcome to the Alembic Club.