Good evening gents. I know there is some information on these fabulous Kässbohrer rigs somewhere on here, but my efforts to find it got bogged down in the pleasures of the other posts in the threads! 
I think the stuff is in either of these threads:
viewtopic.php?f=35&t=16537
viewtopic.php?t=88537
IIRC, there is also some discussion of them on at least one of these Swedish sites:
veteranlastbilar.se/
vespen.se/default.asp?sectio … vespen=mix
I’ll have a proper look tomorrow, or over the weekend. God natt vänner.