I would feel safer with option 1; I would be afraid of the glass cracking or the snake getting burned with option 2. When I had my tank set up I left the CHE resting on top of the screen over the warm side, this worked fine for me temp wise. I eventually stopped using the CHE b/c I ran into humidity problems. I ended up sticking another UTH on the side of my warm side to help me with ambient temps while not sucking up my humidity like the CHE did.