I'm doing a Vulcanus main base playthrough now. It is definitely pretty cool how quickly I can just double production on something I need without needing to setup miners and defenses (though you need cliff explosives on Vulcanus like you need walls on Nauvis).

The big disadvantage of Vulcanus main basing is there are medium asteroids in orbit, so you have to construct your ships carefully. You can't just slap down a large blueprint (well, maybe if you have a whole lot more rocket silos than I do). I have been thinking of making a small blueprint for a ship in orbit so that it can defend itself as I construct it, but I think it's going to be a little tricky.

I'm thinking gleba because I don't wanna deal with freshness or spoilage as much.

Fulgora maybe because it's hard to expand with out personally being there. I can expand nauvis or vulcanus remotely.

You said that one of your reasons is to “take advantage of foundries”, and I wanted to mention that while they must be built on Vulcanus, you can place them on other planets!