Hi,
That sounds good for temp and hum. You can even get it up to 85, AGB's are heat/moisture loving giants
I used to use calcium powder that I bought from the pet store, but now I just supply them with oak leaves. The oak leaves have a calcium like substance, "chitin", in them, and the millis love to eat them! I provide shredded ones (more easily eaten) and whole leaves that the millis like to hide under. The whole ones also keep in the moisture along with sphagnum moss. If you don't have any pesticide free oak leaves near you, you can probably use a cuttle bone for the millis to chew on. I use cuttle bones for my torts as an extra calcium supplement. Or you can buy the powdered calcium from a pet store, but it's somewhat more expensive than the cuttle bone
Hope this helps!
-----
~Sarah
1.1 Mali Uromastyx (Draco and Pumpkin)
0.1 Indian Uromastyx (Cheddar)
1.0.1 Russian Tortoise (Pookie and Kiwi)
6.5.25 Millipedes (8 different species)