are they pets or feeders...
the reason I ask is my pet roaches all have substrate and as natural of an enviroment as I can match. the dubia I keep are feeder insects and honestly there are about 500 of them or so at any given time and cleaning would be a nightmare.
do your pet roaches need substrate? yeah why not, while of course they will get along without it, to me it always looks better for a roach im tryin to view, photograph, or enjoy to have as natural as an environment as I can create.
Not to stray off topic but, I am currently looking for peppered roaches feel free to hit me up if you have too many...