It seems to me that you've boxed your self into a corner. I get the lure of the Polaris. But with only a Carrack and looking at BMM, Polaris and Endeavor, you have only large ships. They are gonna cost more to operate and man compared to a smaller ship. For exploration the Carrack will do, but a smaller multi use ship such as a Dur can be a nice profit maker. If you do decide to get something for space pew-pew, a smaller fighter would be a better choice compared to the Polaris. A Cutlass black would be perfect for that role as it can do the fighter role as well as be a small cargo hauler to make some $$ with. Take yer time and know that what ever ship you miss out on or can't get, it'll probably be available to work on or straight up use from some one here at Test.
Now the disclaimer:
I own a Polaris, Carrack and have a CCU from the Redeemer to the BMM along with some medium and smaller ships.
But I'm a whore and have never been known to take my own advice.