Hello!
Great no calcisand, so do not get it. The people at the petstore are wrong. That is the worst type of sand you can get as it clumps up like cement & cannot be passed well at all. It causes horrific impactions. The only type of sand I will even think about ever using is the washed & sifted playsand. The paper towels or newspaper are fine for now, no problems.
Well, I would say they should be separated around the length of 10-12 inches or so, unless they begin having issues before then. The males can begin "trying" to breed at 6 months of age, but can hurt themselves trying to do so. They neither one are ready at that age.
The reptiglo 10 is fine. Make sure it is 8-10 inches away from your dragon, & the temp gun is great. They work very well.
Are you using any supplementation at all? They need phosphorus free calcium 5 times weekly for babies. You can throw in some D3 as well, since you are using a flourescent bulb.
It sounds like your setup is fine for now, until you have to look into separating them.
Let me know if you need anything.
Tracie