There is a YouTube video that shows how exact those magnets seat into the switch assembly, and the guy wasn't so sure he could get it out safely. That size of ring magnet is quite fragile. He did say he was glad he ordered a second pair with the
mod, so you could get more. I've seen similar sizes-dimensions on eBay, but from a UK supplier. Likely other sizes aren't going to work too well.
Sent from my 4.4'd Nexus 4 using Tapatalk 4