Yes, you can put a CHE on a mesh top as long as it isn't too heavy. I would suggest that you get a lamp dimmer or thermostat to regulate the CHE to the proper temperature.
You will find a lot of different sized BP's at an expo... I would consider a young BP to be 300 grams or less.
Are you talking about the hides sold by reptile basics? if so I would suggest the small size for a 100 gram BP mediums are way too big.