Why do you care?
The instructors most likely to be Team Studio and make the effort to go above and beyond are those who take whatever tools you offer them and run. It can also be those who volunteer the most to cover for others.
The hustle is real, and you want to recognize those who make that extra effort.
Metrics:
FitGrid Pro Sent Rate
Substitutions by that Instructor
What To Do:
Look at your instructor reports
Find the instructors with the highest Subs By stat
Find the instructors with the highest Sent % on FitGrid stat
Consider giving these instructors a small bonus as a recognition of their efforts, or even just sending them a shout out in an email to your staff/instructors