I feed my boy once every two days; he's about 4.5-5 svl. So, roughly the same size as yours. He eats 30-50 large crickets including 10-12 canadian night crawlers every 2 days for 15-20 minutes.

You're not going to overfeed him on invertebrates alone; if you were constantly feeding rodents there would be a problem. Just go by the rule feeding time every 2-3 days: 15-20 minutes. It has always worked for me and around that time he shows signs of being content.