I think inlet port size is related to the rev range over which the motor operates and the cam and exhaust system you use. With a Commando motor, it is probably always better to seek more midrange power and raise the gearing as you go. If you want more acceleration, using more and closer gear ratios can help. The fastest motors are those which can rev higher to develop more power. But a motor which is like that suits the straight parts of a race circuit better. You cannot have it both ways. Either your motor pulls like a train, or it develops more power at high revs. With my bike, If I keep the revs between 5,500 and 7000 and race change with the close box, it is quite fast enough. But you need to be able to do that at every point in corners. If you come out of the corners faster, you will be faster towards the ends of the straights. What really stuffs me is if I get a bad start and not all of the guys in front of me go towards the outside of the corners.
You wil note that the major advances with two stroke motors have been about improving torque In the old days when coming out of corners, you had to get the two stroke upright and pointed before you gave it the berries. In that video I posted about the Mike Hailwood Trophy race at Goodwood, there were TZ 350 Yamahas - no reed valves or controlled exhaust ports..
Getting the steering geometry right is critical. If you cannot gas the bike hard in the middle of a corner, you will be too slow.