Welcome to the RPC!
Warcraft was where I started RPing, though I was originally a heavy PvE/PvPer. I'm still trying to turn over the lore from Azeroth to Eorzea. That'll probably take a while.
Sorry to hear about your free company falling apart and your friend losing interest. Never fun to be alone on the server.
Regardless of whether you are looking to transfer or re-roll, I would most certainly recommend making a character on both Balmung and Gilgamesh and feeling out the communities for yourself. Balmung, by far, is larger in community size, whereas Gilgamesh is tiny and tight-knit. From what you've said, I don't think you'd have a problem fitting in to either of them, and I believe what it would come down to is which one interests you more. My suggestion would be to poke around the Linkshell Hall, perhaps attend one or two of the events on each server, and find which server has your best prime times available.
I know for Gilgamesh, Limsa is our biggest hotspot, and our prime times are generally in the evenings (I'm EST, over here). We also have two events coming up, both of which are on the calender.
If you poke around my neck of the woods, be sure to say hi!