You'll want to feed 10 to 15% of your snakes body weight. I have an adult female I feed 3-4 mice at a feeding. However many mice you need to feed to get to 10-15% is perfect providing that your snake will eat multiple prey items. Some snakes don't mind chowing down on multiples but there are some snakes that will only take one prey item per feeding. Its these kind of snakes that benefit from feeding a larger prey item like a rat or ASF.
But is that based on weekly feeding or once in every 2 or 3 weeks?