Okay sorry for the repetitiveness I just am super nervous about it right now lol. Thankyou for all the information.So just copy and pasting from my prior comment. Keep in mind this info for placement is for use with specifically a T5HO fixture and a 5.0 or 6% strength uvb bulb. If you use any other linear fixture and bulb I would need to know what it is to assist with placement.
UVB should be used. With a T5HO fixture and a 5.0 or 6% bulb you want 8-9 total inches to the branch. HOWEVER babies screen climb... So with that said you have to lift this fixture up off the screen 4 inches. Then the branch would be 4-5 inches down below the screen so that the total distance to branch puts the baby in a 3 uvi level and then the screen would sit at a 6 uvi level which is the top exposure level they should be under.
Once it is safe to add a basking fixture. With a baby screen climbing it has to be lifted quite a bit to avoid thermal burns.
I am just guessing that your house does not get all that cold at night.... I mean if your talking below 60 I would maybe be concerned for a cham that young. They are different than adults in what they can handle. If your house is staying in the 60's and 70's then no it would not be too cold for baby.