Puzzle racer: How many Players?

Sometimes ten Players take part in a race, sometimes only six. How is decided how many participants a race has?

In 10 secs players who joined will play no delaying for the start even if it is 3-6 players,

And only for public race max players: 10 ( I think )

And only for private race like sharing the link to your friends max players: 11 ( I hope so )

@gewetz