Baby grazing

Any tips? Baby is bottle fed (latch issues so I'm an EPer). He will eat 4 oz but some of the time will just eat 2, fall asleep at bottle and I'll wake him up but he'll stop at 2. I give it an hour of changing him and feeding burping etc, then put him in his crib and he wails for more food. He's hungry but I can't spend hours with him grazing. I have a 2 year old too. Any tips? I know they are more efficient with age. Today he cried for a few mins while I was in the bathroom then fell asleep. I feel bad