I've been thinking about this and have a thought. It's really just a small adjustment of what's already been discussed.
The ranking system works off a set of 10 throws. Five confirmed hits are required to move to the next level (league). A slinger is also free to keep working at a particular level if they want to achieve 10/10 perfection. The set of 10 can be cherry-picked from a larger set as discussed earlier.
A slinger's ranking will be a 2 digit number (could be 3, but I don't think anyone will get that high). The first digit is the current distance. A '1' for 10m, '2' for 20m, etc. The second digit is the number of hits. at the distance.
A few examples to demonstrate:
A rank of 32 will mean the slinger has two target hits at 30 meters.
A rank of 25 will mean the slinger has five hits at 20 meters. At this point they can move to 30 meters, or continue working at 20m for a better score at that level.
A rank of 28 will mean the slinger has opted to continue working at 20m, and has eight hits. They can also move to 30 at any time.
If a slinger does get a perfect 10/10 at any level, they will automatically have a ranking for the next distance. So if someone gets 10/10 at 10 meters, their ranking will be 20.
I think the advantages of this method are things are based off an easy to interpret 2-digit number. It also allows two paths if someone wants to chase perfection vs. just advancing to the next level. A slinger's rank will also increase with each additional hit, so there's immediate feedback to feel good about.
On the topic of video evidence, I think we'll be safe in trusting what someone tells us within a particular level. But video will be needed for level advancement. So if I'm just starting out, I can tell everyone that my best was 4 hits at 10m. And my rank is 14 without video (I can provide video for fun and entertainment, but it's not required). If I get 5 hits at 10. and want to move on to 20m, I must provide video confirmation.
Let me know if anything in that explanation isn't clear.
Thoughts?