Ok, here is what I do with my holdbacks as a breeder. I feel that hand feeding from a very young age is very important! It helps with bonding and helps them bond easier with their new owners when they sell because they already trust the human hand!
On one of my off days (from my real job, lol) I hand feed each chameleon. I count how much they eat. I feed them early in the morning and then round about noon again, and then about three hours before bed time (lights off time) again. Let's say the chameleon that is the focus of this note ate a grand total of 15 crickets for the day. Then this is his max, this is me overdoing it! Now, for the next couple of weeks I will feed him two thirds of his max. That means that I will feed him 10 of the same size crickets per day for the next few weeks. Because he is a growing chameleon I need to do the same testing of his maximum capacity in a couple of weeks to addapt for his needs.
This method is the method I use. I am not saying that this method will work for all chameleons and all people, but it works for me because I am the one who raised the chameleons and they trust me. Some chameleons will not hand feed for some people. These people (keepers) will have to addapt this technique to their own situation and chameleon needs.
Hope this helps!