Just a quick update on the progress of the dual-camera IR/VIS system for balloon-mapping kit Kickstarter rewards -- I figured out how to fit some coin cell batteries into the N-type battery holder, which is the same type as the other 12v battery we're using. I used a steel screw to make the battery holder smaller, and it's quite stable.
This hopefully reduces the # of parts you (or we) have to order, and is also helpful because I was having trouble finding battery holders for 3 coin cells.
The other nice thing is that if you buy a pack of 2 12v "A23" batteries, you can peel one open to get 8 1.5v coin cells out. Mathew pointed out that this is kind of a lot to ask people to do, but you can definitely just buy the coin cell batteries on their own, so we can just say it's a nice alternative for those looking to spend less.