You shouldn’t be getting it wet enough to need a drainage layer. It should be just moist enough to not be dusty. Blending it with topsoil (30%-40%) would help considerably.
I would say if u are going bioactive then you will need a drainage lay , just saying DONT ADD TO MUCH WATER otherwise it takes weeks to dry out , hope this helps !
The one time I had a bioactive setup for leopard geckos I didn't use a drainage layer because I wasn't misting or watering (I didn't have plants either, but I did have a dermestid beetle cleanup crew). Another choice if you're really worried about that is to go with the substrate from Josh's frogs that doesn't require a drainage layer (at least not for creatures that don't need as much humidity/misting as frogs). I am using it successfully in a few enclosures for crested or gargoyle geckos and it's been fine even though I'm misting every evening.
Aliza