Unless you have an expensive meter....... I would not recommend for a cage 24x24x48. The reasons are this..... Its best to have 2 basking spots and a place where he or she can be up in the warmth but out of any light rays. His warming spot should not have total UVB directed to it. Here is an example...Say your at the beach all day, Sun Up till Sun Down, you will fry like a potatoe chip if you dont find some shade. A Mercury bulb may work if the warming spot height wont put out too much UVB at that distance, But a Mercury bulb will be in a Dome and he or she should be able to move out of direct exposure. They also emit rays fairly deep into the enclosure making this difficult to get the temp you want at the basking spot. The nice Zoo Med slider Hoods have the basking bulbs at each end for this reason. My new Hood is 36"s and uses a 24" 5.0 tube bulb. The bottom line is.... The Cham can make a choice what light they want.. This is important! My Cham will want UVB for a while then move to his warming spot, then back, what ever he wants. I have found that later in the Afternoon he will be up in the warmth without any direct light at all. General conscensus will recomend the Reptisun 5.0 and warming spots off to 1 side. A big free roam cage will be different. Hope this helped

Dave
Think of your chams living space as 24x24x18 This is the area he will use almost all the time.... Even though its 48"high.Thats not much space really! My new cage is going to be38x28x48 w/ a built in cabinet undreneath