primary chain wear and sprocket movement

[OldStan]

I plan on replacing the parts, I just like to find out (if I can) what causes the problems I find, so I don't miss other necessary repairs. If a shortcut makes sense I'd use it, but that doesn't seem to be the case too often. Checking the basket out closely I see the welding idea would be a really bad thing, putting the stress in the wrong place.

While looking at baskets on Ebay I found two different styles. One is with large rivets retaining the sprocket directly to the basket, the other (like mine) with the sprocket retained by a plate with smaller rivets. Is one for the CA and the other for the CB?CL? Are they interchangeable, and if so, which one is preferable?