We tried continuent a year or two ago and gave up. And our database was small (couple hundred megs). We had three nodes and had problems with a node crashing bringing the other nodes down. With the result being we had to power cycle each of the boxes. We never made it to production.
That said, it was about two years ago. Hopefully it's improved, but I've been soured by the experience. Also, that wasn't sequoia, it was their commercial offering. No idea what difference that makes.
In our case we ended up just using a single master with multiple slaves and the mysql_replication_adapter to spread the load.
That kind of replication is more than you really want to have on a simple master-master or master-slave replication. Your better off bringing in someone with experience with that scale of DB, and using whatever they recommend to you.