The capital ship itself is pretty important. His abilities being upgraded make a big difference. His ability block lands more consistently, he gives more TM, and his ultimate ability hits like the animation makes it look like it will, like a stampede! That ability alone has saved me in arena MANY times.
I just realized I was wrong about one of the ships I used. TFP is one of my strongest ships and he works great with Tarkin. Any time he dodges an attack it gives the capital ship TM. I did NOT use JC's ship. I used TFP.
Probably still doable either way but thought I should clarify.