haha i did the same thing i made a whole cage thing that went all the way around the viv and i hated the dam thing so i ripped it out lol im not trying a fake rock ever again im just going to stick with logs
One way is to make everything in place, to be sure that it fits, http://www.leopardgecko-uppfodarna.com/productssimple1.html like this, im going to make something like this when i get my Bearded Dragon (Skäggagam in swedish^^) only the vivarium will be 160x70x70cm and somewhat brighter surface than that
EDIT: You have to scroll down a bit