The best feeder is variety feeder.

I don't like using the word staple.
That word has connotations that the chameleon will be mostly fed on that feeder too often.
Silkies, albeit its close to ideal calcium to phospor ratio, cannot be used solely as your chameleon feeder. Their lack of chitin can cause problem to your chameleon. So, crickets or roaches are also essential for your chameleon's diet.
Hornworms has better protein and water content. So, Hornworms are perfect for hydration and also for sick chameleon.
If you want a happy chameleon, give it a variety of diets.
here are examples of feeders I give to them:
silkies, horwnworms, crickets, mantises, butterflies (painted lady and cabbage white only), occasional locusts and katydids (if I can find one), butterworms, superworms, flies (blue bottle for adult and house flies for pygmies), damselfly, and occasionally moths from silkies and hornworms.