I agree that overly large carbs are not needed in many applications and that a simply a larger carb will not yeild more power for that mod alone. For example often stock mobys will have better performance when using a 14:12 carb rather than a 15:15 carb this is because the emulsion tubes on the 14:12 are more appropriately metering fuel for the design of the av7 motor, the 15:15 emulsion tube is simply the wrong jetting and results in a low end bog.
Proper tuning any carb and motor will yield better results than just a larger size or smaller size alone. i use a 19mm carb on my polini 4 pedal setup because thats the size of the intake tract. why would i choke the circuit with a 15mm phbg, i certainly won't get more power from the 15mm carb if it restricts my intake tract, however i doubt i will see much gain if i implement a 21mm phbg.
I always call that jet a pilot jet because i want to dispel the myth that it is only for an idle function. the choke jet does nothing but enrichens the air fuel mix with more fuel when engaged (by fuel i assume everyone knows not strait gasoline but premix.. another word choice issue that happens alot)
my biggest pet peeve on here is number and theory slingin ppl who don't even have a fast bike ;)