Growth rate really depends on the snake. Everyone is different.
I have 4 late 2011 girls all born within a month of each other. The oldest is the smallest(500g) and the youngest is the largest (1400 g).
They are all on the same feeding schedules and haven't missed a meal. The largest is just a weed and has a very aggressive feeding response.
I have all my hatchlings on 4 day feeding schedules. Once they hit 500 grams, they are bumped to a 7 day feeding schedule.
My adults are fed every 7-10 days. I feed the appropriately sized food. I don't weight my rats. I just eyeball the size of rat to the snake's mid-section.
But all my adults, regardless of size, are fed small rats. I feed live, so it's just safer for the snakes if I feed multiple smalls than one large rat.