The general rule of thumb is, don't feed them anything bigger than the space between their eyes. The rule can be bent a bit for softer feeders like silkworms and hornworms, usually, but I'm not sure about crickets. Do you have a picture of your little guy?
I don't see medium sized crickets being an issue for him. He looks about the size that my cham was when I got her and I was quick to upgrade her from small to medium crickets because she was eating the small ones like they were crumbs lol.
Haha thats exactly my problem. I went through 100 small crickets in a few days lmao. Like i said he doesnt even chew them. I figure medium would be okay. Probably more fun/rewarding for him to hunt anyway. Plus they wont fit under my water collection bin at the bottom like the small ones do