First, I would not be feeding chams that size, crickets that size. I think the rule of thumb, and correct me if I am wrong, is an insect size should be no longer than the width of the mouth. Now, I know supers will not make this, but most insects are a little longer than the chams mouth is wide. I think the important thing to get is not to provide items so large that your cham may choke on. Most of the time they will accept smaller items and I have read that smaller crix retain nutrition better than older ones. Maybe that was because their gut was larger in proportion to the rest of their body thus giving the cham more raw gutload.
Another concept that I will leave open is how much to feed. This varies by the specimen, but I believe people are relying on the cham's weight and the weight of the prey food daily fed. Any comments?
I also have heard to go sparingly with the supers and diversify your diet. I try to split the main staples between crix, silks and roaches, then offer supers, hornworms, other roaches and the occasional ghopper and wild caught stuff.
Supers last a long time, so keep them, and there are resources on the web that tell you how to breed them. Or just leave them out for the Blue Jays.
Chams will eat roaches, but give them appropriatel sized prey. Mine seem to be drawn to lighter or redder colored ones. They especially love periplaneta americata, American Cockroach or 'palmetto bugs' as the reds call them and the Surinam roach, Pycnoscelus surinamensis, but both climb.
As for what they'll eat at an age, they have preferences like us, just offer a variety of foods. I have had a cham eat nothing but supers and wax when he got older, and it took awhile to break him from it; it was just possible he preferred to binge on McD's for awhile. It will be more difficult for you to offer a diverse diet, but better for them. And, if you are having trouble getting one to eat, having something different may get them to resume feeding.