Leaf litter holds moisture very well I just keep the bottom inch dark and it keeps my humidity high it's perfect
I hate coir for anything I've tried it in the past and will never use it again I find it dries out easily and goes powdery and has no function or nutrition especially for Pods etc
My go to perfect sub is forest floor for anything it holds moisture well it's very nutritious for anything that eats sub totally natural I use it for Roaches Pods spiders centipedes pet much everything
I also like live Moss but with a good inch+ of roots (yes I know it doesn't have roots they're rhizomes) that is a fantastic moisture holder as the roots never dry out even if it's neglected for a couple of weeks and it's perfect I have a quarter to a third of the tub depending on species with love Moss
How this helps
SB