On the subject of league courses being less difficult than GP courses, is it feasible to simply relate a person's hit rate at home with their hit rate on the GP circuit?
For example, the last time I checked (as scores sec for the region) our regular GP shooters were if anything knocking a higher proportion of targets down at GPs than they were at our home regional league shoots. Maybe that means our home courses are too difficult.
But when I heard from one club - not in our region -
- that they have gimme targets like 18 yard full size kill freestyles in their league shoots, I can see that a few of them in a course would soon give an artificially high average.
On the subject of rolling 20 scores, I would consider any score more than 12 months old to be of much lower use in determining a person's current true ability.