You are doing fine, you can allow the moss to be a bit more dripping wet if you want to keep it moist long enough. But if you have your moist hide sitting directly above the UTH, it will dry out faster, and there's not much you can do about it. However leopard geckos don't need a completely moist hide 100% of the time so having it dry during the day while they sleep is fine. You could place the moist hide in a way that half of it is over warn floor, the other half cool. Doing it this way may allow you to keep the moisture inside the moisthide longer.
Also depends on what you use as your moist hide container. If you use a container with the opening on the top, try one with an opening on the side so moisture does not escape as easy.
With regards to sphagnum moss, I feel I should toss in an user warning. Leopard geckos are known to ingest sphagnum moss at times. And as you can see how the moss is, it's not digestible. So sometimes they get impacted due to sphagnum moss. It's a warning you don't hear often, but impaction from sphagnum moss happens more than you think with leopard geckos. Just google it up and you will find plenty of forum threads and ugly pictures of this happening.
I saw this happen not with my own geckos, but with someone else's. Ever since then I've used wet paper towels as the moist hide medium. It works well for me and I'm happy to not have to worry about impaction risk. Some people also use cocofiber, which is also a fine alternative to sphagnum moss. Cocofiber is small enough that if ingested, they don't seem to have that negative effect that sphagnum moss have.
Anyways, thought I'd toss these ideas out there. You as the owner gets to decide what's best for your own pets. Good luck
