Been a while since I was playing with 650 upwards Triumph twins. When I was, general consensus was that 30mm carbs were only for girls, 32s were popular, as was boring out mk1 carbs to 33.5mm, and guys running mk2s ran all sorts of sizes right up to 38mm.
What's the thinking these days for a fast fun road bike? I can't help thinking that 30mm was probably fine all along!!