For a cruising cat:
36 inches is a rule of thumb at the bow, it's the underbody that matters (and what slams disconcertingly). I don't have a number there, but more than the Gemini's 15 inches
is a good number.
depends, classical is 9:1 - but for weight carrying capacity less is best. Depends more on where it's 'fat', bows that are too sharp require care as they will plunge and pitch pole.
Yes, traveler isn't just for pointing, it's for trim/balance and heeling also. Very important.