Hey Tars ,
I would suggest you get some dubia/orange spotted or Turkish roaches ..as they can't climb smooth surfaces
Thou dubias should be used for larger aggressive eaters because if they are not eaten immediately they tend to burrow in the substrate ..turkish roaches are a good choice as they don't burrow and breed easily .
I currently have a colony of turkistans mixed with a few dubias and they are doing fine .
Take a look here at how to setup your roaches :
www.tarantulas.co.za/forum/feeders/58322-what-am-i-doing-wrong
Hope this helps