On the range, find the average distance you hit balls from each hour (7 to 11) on the clock.
Using a clock as a visualization for the back swing will make chipping to certain distances easy and consistent.
Finding the distances from each hour on the clock should take no more than 2 hours if you hit 5 to 10 balls for each position.
Practice swinging with the same tempo on each chip for the best consistency.
Almost every tour pro uses this method for distances inside 100 yards, and Dave Pelz writes about the method in his book "The Short Game Bible."