Cheaper on banggood, similar spec too. It will take any 1500-1800mah 4s from what I have seen, so you don’t just have to buy the FT store one, unless you want to support FT with purchases of course! Rotor Riot have one at a good price as well.
I think you should run a 1300 to start with. I always go with the lightest battery option on anything new, since a bit of extra capacity is usually offset by greater weight. I didn’t realise the Hawk wanted a smaller battery, makes sense.