If that tank is glass, don't do it! The sun will turn the tank into a literal oven for your lizards. The same with lights, just on a smaller scale - that's why it's important to have a thermometer to check temps all the time on your animals.
What I've gotten from others is perfect: get a large plastic container (at least the size of a 20gal tank, if not the size of a 40 or bigger!), cut out the top and sides, and use a hot glue gun to firmly attach screening to the holes. This will be a nice, light-weight, not-too-hot enclosure for them. Just make sure you provide them some shade (hides are the best), water out of the sun, and check on them frequently just to be sure.
You could also make a cage yourself with wood and hardware cloth (1/2" should be fine), and provide all the same things. As long as there is shade and water always available, there's not any need to worry.
Good luck!