Thanks again for your e-mail earlier today. I have two additional questions that I had not thought of earlier.
First, where did you find the black plastic glass track? I've been using the Knap and Vogt "tan" product that is actually orange.
Second, how tall is the lower lip of the cage? I've been struggling to come up with the ideal height. Too low and substrate can end up in the track, too high and cleaning is more difficult. Of course this is not a huge issue with GTP's so you might not have worried about this much.