Hi, great questions!
You can pick any size ship you would like, they each have their own ability that can help determine what your character is like - as the rig is an extension of the character...
You can do full FP or you can roll your rig die at character creation and see how much you start with.
The way this balances out is that the smaller the ship, the higher the chance you roll a one - which just lets you jump without spending FP. The bigger the ship, the more "negative" encounters you can potentially roll on the NAV table. And if playing Co-op there are more incentives to have Rigs of different sizes in your convoy.
Thank you so much for giving it a look over, its one of my favorite games i've made!