Board Game Arena

Irish Gauge is available here, for anyone that didn't know.

I've only played it twice so far, so by no means an experienced player. I agree that this is a difficult and subtle decision. Here are some of my thoughts (just for base game, no variant). Think about what colors you want to be strong and what colors you want to be weak. Whatever you have a lot of, ...

It's not common that you'll acquire multiple copies of every card you want to use in the course of a game, sometimes you need a second Mercator or Architect in a cycle before you Tribune. Those are common targets, especially the upgraded Mercator. Prefect, Senator, and Consul are also common targets...