I'm currently holding 1-2 without buying any of the ships, although I'm planning to buy slave 1 and either cassian's or kylo's ship. I can't decide. But looking at prepping for zetas when they're avai...
The zeta challenge drop rate is shambolic though. You should farm those DS ships, but expect buying zetas to be the way to go, with the occasional zeta or two dropping from said challenge once in a while.