Well it sounds like you got it down. The positioning of the two flower pots are right on, and you can go ahead and change them whenever. As for the zip lock, you only ever use those for humid hides. Because your main hides should be opaque, so the flower pots are pretty good. If you are looking for professional hides, Reptiles Basics are really good: http://www.reptilebasics.com/Hide-Boxes-p-1-c-282.html

And it sounds like your humidity is holding up well too. As long as humidity and temperature and at the proper level and they are constant, and you providing enough security for your snake, you are fine.

You can always post pictures of your tank, so we get the exact sense of what's going on.