The party that strikes the mob first is usually the one who gets the most out of it. That leads me to believe these mobs are 'contested content'. Contested meaning whoever gets there first, gets the lion's share. There is no need to wait on the whole server to get there.

Nobody can give a clear answer on how long or for how many people should wait. Well I can. Wait till your party has shown up. Once everyone in the party is situated, pull it, kill it, and move on. Congrats on getting the seals.

This isn't being selfish or mean either. When the hunts first came out. I tried the waiting thing. I was able to get literally 30+ people there waiting until there was no one else 'on the way'. We pulled, mob died in 5 seconds, my group got no credit despite being the first ones there and doing the so called 'right thing' by waiting. That means these mobs were meant to be competitive.

There's always the duty finder to get myth/sold in a non-competitive environment.