So I'm not convinced that a ton of people realize this...mainly because I've heard no mention of it before, but I noticed some differences in two rear clutches that I have.
So this one is the original clutch I was running. To my measurements it has a 9 3/16mm plate. It also has large clutch pads.
On closer comparison you can see that the second clutch has a larger plate (10 3/16mm). This would allow for more bottom end than the smaller plate. Since both have the same inner piece this would not affect top speed. This smaller clutch also has smaller pads.
The coolest realization from all of this came when I took the clutch apart to clean it out. The second clutch is stamped with the vespa logo and a "2". It uses clutch springs that resemble those used for non-variating ciao clutches...the first clutch has springs with one longer side. This means something to me because a while back I ordered variating malossi clutch springs from treats; tried to install them, but couldn't because they did not have the long side that was needed...See this link for clutch number 1 innards...Notice the long sided spring? The second clutch has same sided springs, making the malossi springs usable.
I'll try to get pictures of inside the clutches so that this makes a little more sense to people other than me...
So this is what the inside of the clutch looks like. Pretty much similar except for the small, even sided springs. You also can see the vespa and #2 stamp.