I have the Topfin divider. I have not made any myself, I am not sure what I would need to do that.
The biggest problem I am having right now is how to get it to stay put in my 10 gal. tank. It comes with two hooks that are supposed to hook on the outside of the top, but this blocks my hood from going on securely. The only other option I see to securing it would be to use aquarium sealant to glue it to the tank. I am kind of scared to do this because i don't know if I will be able to get it off the tank if I take out or move the divider.