this is what works for me and i was suggested it by azreptile and some other herpvets near the valley.
cypress mulch mixed with some moss. the moss helps with moisture and softening the mulch up a bit.and add some moss on top of the substrate in some spots.
one herpvet even suggested dont worry about the humidity in the enclosure itself but offer a humid hide as the bps come out at night when the humidity is down and the air and land are dryer.he said bps live in burrows and the humidity idea comes from humid burrows bps chill in during the day to escape the heat and move closer to the surface when they need more warmth.
i experimented with these humid hides and found my bp only liked a humid hide on the warmer areas of the tank and the other hides normal.but i dont have problems with humidity anymore thanks to the mulch moss mixture.i still offer a humid hide though