When I taught Language Arts we had a chart where you cross-referenced the grade level score from the STAR test with how many points a student’s goal should be.
The calculator found here does that. It also factors in how much practice time a student has for independent reading in addition to how long the goal period is.
You can create a roster from the web page. The nicer feature would be to include the source code for this directly in your Reading Renaissance account where your rosters were already created.