I can guarantee this because like I said I have the same tank (so obviously the same black plastic bars) and I use a CHE exactly as he is describing and it's 100W and I have it turned full heat and it's always resting on those bars. I covered it with the aluminum foil tape and haven't had any issues. The bars don't even get very hot.
I'm just saying it's safe because I've been through this and tested it and it is safe to place on those bars.