I’ve got them fitted inside the springs as ‘helper springs’. Can’t remember offhand where I got them but mine has slightly taller springs, 30mm or so, and they work really well. I don’t remember ordering anything special but I guess if there’s a big lift they could do either taller bags or a spacer.
They’ve helped level the ol’ girl up a treat with the constant weight I have in the back. No more saggy bottom!! Pretty easy fit too by removing the bump stop cone.
I’ve a feeling I found out Karl was doing them after I bought and fitted them.