Multi master setup in Mariadb 10.0

Hi Is there a upper limit of masters in multi master replication ? I'm migrating old environment (Master-Master-Slave) to new data center, Where I will also have Master-Master-Slave, but during the migration and test phase, I would like to extend the replication to 4 masters with 2 slaves.

I have tested the following setup A <=> B <=> C Where A and C are slave of B and B is slave of A and C. If I set log_slave_updates as true on all servers, and I insert a row in A replication on B will fail with duplicate key insert when the bin log is read from C. If only B has log_slave_updates as true it works, but then the max number of masters is 3 ?

Is it perhaps better to have log_slave_updates false, and configure all servers I want to have as master as a slave from each and every other master ?

Or is ring replication the way to go ? I know of Galera cluster and we are looking into that, but I think it will take more time to test so that is a down the road.