I see you mentioning to go for Grand Moff Tarkin as your prime capital ship, but Ackbar is off the bat the strongest capital ship. Grand Moff Tarkin are better in special fleet comps, the word around is. If you do really well in fleet from the very beginning, throughout mid and late game, you'll get tons of fleet currency. If you spend that currency on ship blueprints you'll be able to get 5 4* dark side ships and 8 5* ships before everyone else.
If you decide to be less focused on ships and farm toon shards out of the fleet shop, you should then go for Grand Moff Tarkin, so you'll minimize the resources needed for the zeta challenge.
