Hey, I'll test your game for the full 14 days — been in your exact position before. If it's useful, I built a small tool (PeerPlay) that handles this kind of reciprocal testing automatically so you don't have to manually track who's opted in and for how long, but happy to just do this directly too if that's simpler for you.
https://play.google.com/store/apps/details?id=com.testerhub.app