indeed, they're to compensate on the toe out, which happens if you lower your cossie. Can't anything about that besides shims or adjustable rearbeam to correct. I also have those shims, but i've got also camber correction shims made up a while ago. (just haven't found the time to put them in place, (had some Amsterdam-Dakar challenge things to do )) At the moment the rear has 2degrees camber, after shimming itīll be between 0 and 0,5 camber. When about to fit those, the solid rear beammount, along with the solid diffhanger will in placement aswell.
Should improve the rear-end quite a bit on track
cheers