Help. Need some suggestions on starbases. I'm working hard to understand this game and am unclear on a few things:

Economic starbases: Do they collect taxes from all trade routes in their area of effect or just yours? Any way to see how much I'm earning? I know trade routes earn you more the further away they are from their home. Does that mean putting economic starbases at the trade route destination point will earn you more BCs?

Influence starbases: Does their influence only affect their radius? If the game progresses and the influence border moves beyond the radius of a starbase, is it contributing at all? In my last game, I had one of the weaker races pinned in a corner and placed 3 starbases around them and flipped them. Now that they are mine, and the planets are generating more than enough influence to keep them mine, are the stabases useless?

Thanks in advance!