Yes making the weights lighter will increase RPM's but the down side to that is you will be losing the benifits you gained with decreased belt slip. However if you add a stiffer spring you will also raise rpms more effectively.
What I was saying by adding the bolt to the heel is you can get an even faster shift out, provided you have the rpms to do it. Higher rpm's at engagment is a false sense of power. his bike may not wheelie in low like it did before. However he is pulling harder, and not just reving high and jumping into gear. The high rpm engagment is also hard on the bike especially with those big ol tires he has.

In my opinion I think he has the wrong pipe for his application.