I think basically you have to work out the hull lengths conducive to the cabin you want
while keeping in mind at 30ft WW hull sizes a full headroom hull looks a little tall
Then perhaps decide on galley up/down

As for the styling of the boat, I think this has largely come to be due to using flat panel infusion methods, and I agree Steiner has a good hand when it comes to the look of the boat.

There are lessons to be gleaned from the pocket cats such as Prouts 26ft Sirocco, which manages a good head height while not looking like it has a lot of windage, something to do with a finely crafted cabin top, generous knuckle and domed cabin roof.