Generally speaking, avoid the start and finish lines and all marks like the plague.

There are no rules that give racing sailors specific rights over non-racing vessels. They need to obey rules-of-the-road when in the vicinity of other vessels, which includes giving way to ships in a channel, etc.

Of course, you are a racing sailor and want to be kind and not force them to deal with you. Etiquette says when near the other boats, sail slower than they are, and duck everyone well in advance. And, as mentioned, don't sit on their wind.

Mike