You are barking up the wrong tree...
From a power perspective it is not so much the carb size that matters as it is the design of the entire intake. The more air you can get into the engine (the more fuel you can add) the more power you can make. Air does not like sharp corners or other direction changes. It slows things down and creates turbulence which is not good over your wings and even worse in your intake.
The carb needs to accomplish two things: A) it needs to feed the right metered amount of fuel into the intake air stream and B) it needs to convert liquid fuel that does not burn well to "atomized" fuel that does burn well. Honestly both of these things favor using a smaller carb throat diameter to maintain higher velocity of the air flow through the carb. Go too big and you lose vacuum signal to pull fuel from the float bowl and, because pressure transitions help break up the fuel droplets, you also lose fuel atomization.
Length of intake has some impact as well with longer intakes providing potential improvement in intake tuning (just like exhaust headers) at the expense of fuel condensing on the intake and not making it to the cylinder.
Hanging a Mikuni off the cylinder head is crude but works because it provides a very clear straight in air flow to the engine. There is also some increase in vacuum pulses with the short distance from individual carb to intake valve.
Many typical carb/intake designs involve a sharp 90 degree turn right at the carb. These are horrible air paths and kill power.
So focus on the intake design and pick a carb that works with that.
