Fleet Store: No hoarding necessary
1. Darth Vader
2. General Grievous
3. TIE Adv.
4. Rex's ARC-170
5. Ghost
6. Phantom
7. Poe's X-Wing
8. Scimitar
9. Slave 1
10. Gauntlet
Now, the first 4 are all rare, so you might be able to farm all of them at once. Just make sure you never drop below 1k currency unless you're buying whichever character or ship is at the top of the list. There is no need to worry about hoarding since Vader & Grievous aren't on the list of characters that will have their shards doubled.
After you're done with Vader, Grievous & the Ships here, there are a couple other characters that are exclusive here (or difficult to get elsewhere) that you should pick up. Both of these characters have their shards doubled, but you don't have to worry about waiting since it's going to take you months before you're ready to pick them up:
1. Chirrut
2. Ahsoka Tano (Fulcrum)
After that, you're ready to turn your Fleet Tokens into zeta mats forever.
