I didn't see the guarantee. Thanks for looking Renate.
It appears the original battery was 2800 mAh.
https://goodereader.com/blog/product...owlight-stylus
https://productz.com/en/onyx-boox-no...bwg#full-specs
So I think I'll go for the lower capacity battery. It will suffice, is lower tech, and hopefully less likely to explode.
Oddly enough, I think I'm going to go with the cheapest, weakest unmarked battery. The seller has been around for the longest and has the highest rating. It's a crapshoot anyway.