my personal preference in this situtation would be a single pain that opens down. if you open it up, you have to be abel to hold it there to work in the tank. opening down gravity willl hold it for you. i wouldnt worry too much about the hinge holing your glass inthat arrangement either. however, if you hang a piece of glass that size from the side, youll have to get some serious adhesive, or some thin glass.
i steer away from acrylic because of the warping, and scratching issues.
for venting, some sort of air flow just abovethe glass is usually reccomended. ive found air flow anywhere in the viv will eliminate moisture on the glass. my prefered method for this is a screen area towards the front, or a 1 1/2" fan, or a combination of the two. its more important for your frogs and plants to have proper humidity levels, than it is for them to have clear glass. remember that!
