how does potential work in terms of hwo many you can use on a weapon?

ah ic. thanks.

So if you obtain an item which has hidden potential and you identify it (with magnifying glass), then you can't use a potential scroll of it anymore?

Also, is it complete random what type of stats it can get?

Yep and yep (there actually a pool from which it picks what potential it would give and there are different pools for type of item and potential tier (item level: 0-30, 31-70, 71-200)), only way to change what it gives is with miracle cubes.