I mean 30-50% is what I've read is good for an ambient for Russians with higher humidity in moist hides.
I live in Georgia, in the US, I'm not 100% sure what our usual humidity is, but I know it's pretty high in the summers.
I am thinking I may very well try to replicate a natural habitat as much as possible for him. I'm considering doing a very large tortoise table set up with regular misting/watering, moist hides, and possibly fully planting it with grass and edible weeds.
Humid hides help but they dont make up for lack of humidity in general. 50-70% is more appropriate for a russian in captivity, they can tolerate lower as adults but it isnt great for them, 30-50 is the same old stuff about them being desert animals etc. . .