This is funny. I had this issue today. I have a 4 Chams at the moment and find it harder to moitor feedings. They have all started to ignore the feeding cups and only feed once they get free-ranges and climb the screen of from my hand. Weird!!
I honestly think that feeding cup idea with the glued screen on the inside for the crickets to climb will work well. (same idea, but they are somewhat contained)
i'll try to find the link to it.