Keep the scale for weighing your snake, not his food. That's just making things complicated and confusing for you. Personally, I would try switching him to rats. He's big enough for pups or small weaned rats. If you want to stick with mice, just keep feeding him the way you have. If he'll take two at a time, feed him two at a time. If not, just give him one, but you'll eventually need to feed multiple mice per feeding once he gets bigger. That's one of the reasons it's easier to feed rats.