Indeed Sced, Pheidola pallidula like it dry i keep them in about 40%. (mine are in a sand nest) I like the nest, its nice but as Mpir sad, it is difficult to feed them in this setup. Also it is good for a few years, if the colony is getting bigger you need to move them to a bigger farm.
About gliding material, PTFE GP1 is the best, it stays on the longest, when to replace it ? when your ants can walk on it.

If you use paraffin oil you need to replace it every 3 months (depends on the weather, if it is warm outside you need to replace it sooner)
I just look at my ants, if they can walk on the glide material i replace it.
Greets