mysql replication and rails

i would like to use some kind of replication (master -> slave or,
better, master <-> master) to provide better performance and fail-
as i read, multi-master replication in mysql is quite problematic: i'm
talking about duplicate key problem.

so i was searching about plugins that make rails aware of a master-
slave setup.
masochims seems to be nice.
have you tried it?
i would like to use master for writes (obviously) and [master, slave]
for reads. is it possible? is it possible to add more then one slave
to database.yml?
i didn't test it by myself because of the lack of a decent computer,
capable to run two mysql server.