Right now, I'm leaning toward Rusty Chile. The hot-pink color option for Peru will still come in handy, however, as we were already planning to use that for Monash (one of the powers in the 11-player Escalation version of the map).
Below are what those colors look like along with custom units. Hex/sail units won't be available for Escalation, but a set is shown here for Monash to provide some idea of what its unit colors will look like against terrain.
