Hold on hold on Andrew we'll get to that, I wanted to comment on the strength of the clutch teeth themselves.
I've just compared three clutch baskets, one brand new, the other with 3396 miles, and the last with 7450 miles. Not much difference at all between the first two except the 3396 one has some slight glazing on the clutch basket walls, quite good. The last one with 7450 miles is showing some more glazing on the walls compared to the 3396miler and the basket itself is discoloured, you can see some clear signs of wear on the teeth of the clutch but it still grooves nicely with the main gear, there is no noticeable play between the teeth.
As for the clutch basket internals they are a different story. The new one of course, looks perfect. The 3396miler has the clutch disks themselves feeling slightly more pliable and there's a measureable gap between the disk at the clutch arms, about 0.5mm, everything else looks pretty much the same as the new one including the plates.
On the 7450miler the clutch disks have quite noticeable play between the clutch basket's arms, a little more than 1mm, the ballbearing basket at the bottom of the clutch is easier to twist and bend and the cluch plates are discoloured (although this may be due to wrong transmission fluid).
I really don't think that the clutch basket or its teeth are weak in any way, the one to consistently look shitty as the miles creep up and up are the clutch disks. I've had a 64.5cc kit on my clutch basket for two years now and about 2000 miles with zero change in the wear on the teeth and I tear apart all my motors twice a year. If anything goes and goes fast on the Sachs clutch it would be the disks.