Welcome! You can check my build out and rob ideas away. The toggle clamps that Dragons Breath has on his tank can be bought direct from the maunfacturer for about $5.50 each. The website is called "The Toggle Store". I started this with a whim not knowing I would end up loving this and having one heck of a sense of fulfillment as I went along. If you ever are stuck just ask and people here will help you, me included.
Your door dilemma is just that. I like the dual doors on opposite sides for your size tank. I figured out how to make one of my tanks with a removable rib and rails so it will accept a whole hog. I am partial to my 3 doors because of heat loss.
Good luck and I will be deffinately be watching your build.