ok so here it goes....ive been building racks for years now and i can almost do it in my sleep....my problem is now i want to build cages.....now i get what materials to use, heating, lighting, and vents....what i dont get is the doors...im gonna make sliding glass doors an i know the measurements what i dont know is glass or acrylic??? how thick??? where to get the glass??? and where to get the tracks???? however i do understand how to install them......any help would be really appreciated THANKS