Looks like I’m already using what most folks found to be best to track chains. The good old ziplock.
Note for those trying to figure which is 11 vs 12, the quick link and chain links should have 11s or 12s on the links (Shimano).
For those wondering how to track usage, I use probikegarage app for all my components and all bikes. It syncs with Strava for distance used so once you setup a component it’s easy to use. You just swap chain 1 for chain 2 once it reminds you of total mileage over a specified distance. I read 500 miles somewhere so that’s what I’ve started with. We will see how quickly it gets old to change chains every 4 weeks, and rewax every 12 weeks (I switch between 3 chains)