Inspired from Maghex, I decided to model a similar magnetic system that is compatible with Axolote Hex tile system.
It uses 5x2mm magnets which you can order cheap from china. It uses 7 magnets per connector and 1 per top-facing tile. Depending on how many tiles you want, I would recommend to buy 2000 magnets, that way you have plenty of magnets for the top-facing axlote tiles as well!
IMPORTANT! Remember to insert the magnets with opposite polarity. Otherwise they will repel instead of pulling each other.
The magnets should be "press to fit". So no glue needed. If you are using this with axolote hex tiles, you have to glue a magnet or metal washer underneath each top-facing axlote tile (see example pictures). It takes some time to fit all the magnets, but in the end, it's worth it. Setting up and tear down scenarios is very easy when the magnets snaps everything together.