How long is a tail in this measurement system?
I think it depends on how tall Reyn are. If they're like human-sized I'd guess 3-4 feet, maybe a meter?
I think its shorter then that. But its hard to tell considering the only other time its been used was back in page 209. And considering he was standing a small field and was measured about 20 tails diameter, I'm thinking its closer to 2 feet, 2.5 at the most.