Do the rules allow a disk clutch? If not, my preference would be the clutch that is the most easily adjusted for the slip RPM. Of course durability is important and that has to be a modifier to the easiness of adjustment. Also, within the 1st 2 parameters, you want the heaviest shoes with the strongest spring.
Do rules dictate type ?
Drum , noram ge is cheap and durable . Changing gears you have too buy a drum that offsets any cost saving . The hillard is good and quite popular . We used the fury simplest and cheapest yet got the job done .
Disc bully is my choice but any of the new ones would work .
Do not buy a used disc clutch without seeing it in person .