Welcome back to FFXI! I'm sure you'll find plenty of fun times again.
For duo'ing, you have a great idea with tank and support. However, please consider duo BST, as that's just incredibly great too!
Benefits of BST Duo:
No waiting for party invites.
Plenty of Beastmen Seals/Kindred Seals to share.
Great exposure to hate control dynamics.
Opportunity to learn the basics of both melee and mage jobs (to some degree).
At 75, there are many, many things that 2 BSTs can do with ease that other combinations can't do or just can't do as efficiently.
Above all else, do what's fun! Never forget this is a game, and you should enjoy yourselves!
Once again, welcome.
