My adult male corn is about 4 ft long, 670g. He eats one jumbo mouse (35-40g) or small rat (40-60g_ every 7-10 days. When I fed him this much once a week he was starting to get a little fat so I scaled back a little.

I've seen FT "large adult mice" that weighed only 17g so 3 of them if that small isn't all that much.