The reason why mounting the flyweights in between the post gives better performance is because it somehow makes the flyweights "heavier" mounted in this position and the axial force throws the flyweights axially towards the clutchshoe / clutchbell at a greater force.

I've tried making the flyweights heavier by using 2 pieces of M3 x 4 grub / set screws on each flyweight and mounted the flyweights in between the flywheel pins. Yellow shoes and the harder Centax II spring is used. But like what Pyramid experienced, it gives very good performance initially but the clutch somehow gets stuck intermittently going out of the corners after a while. Probably after it gets heated up.

So now I just cut the flyweights and mount them in between the flywheel pins.

What I do lighten is by drilling and making several dimple holes BEHIND the clutchshoe with a bodyshell reamer in order to make the clutchshoe lighter. I saw this being done by Rick V but that was on a 950R.

He explains that a lighter clutchshoe accelerates faster towards the clutchbell due to the axial force from the flyweights. This results in a more responsive clutch.