I'm thinking about getting some medium-sized magnetic ledges for my scalebabies, and wanted to get some opinions. These are the ones that look like rock ledges (or mushrooms - saw those, too), and "clamp" on the glass side of the enclosures with magnets. I didn't see any sharp edges that might cause injury. The glass on my enclosures is thinner than aquarium glass (for lighter weight). Who has used these? Are you happy with them? No cracked glass? Any cleaning issues? Would you recommend?