I understand your concern. It really is hard to keep the humidity up without having a soggy bottom which can be a problem for rot. We end up spraying the glass sides several times a day. But I am considering a fogger. The area directly under the heating element dries out so fast. I use a mix of "Forrest floor" and coco coir.
If you offer deep substrate (6 inches or so) then you can add water to the substrate at a couple different spots...then cover most of the top of the enclosure...this will offer you up good humidity without it becoming soggy bottom city....
Also...don't forget to keep the temps day and night no less than 80 ish..
What everybody else said and I also put a heat cord at the bottom of the substrate that really helps as well.
Also just want to point something out, its probably a typo but you said if "humidity gets too high, it causes pyramiding." Low humidity causes pyramiding (along with multiple other factors) so keep that humidity high!