Hi,
I think dubia is good as a staple, but it is highly recommended to feed as many kind of insects as many you can! (just imagine if you only could eat grill chicken with fried potatoes ONLY!) Try some crix, roaches, silk and hornworms, superworms etc... searc for them at the site sponsors, im sure you will find a lot.
Dubia (and crix and supers) can feed with dog/cat food as a protein source, thats why they are high in protein, which is NOT good for the chameleons, it can cause gout. So you need to gutload the feeders 24 hours before feeding up!
So in my opinion its bad to use only one feeder.