Thank you for your quick answer

I have now been grinding for about one hour on one strut.
I got curious so I took out one Tokico (spell?) non-AAS strut and to my surprise I only had to grind on 2 spots to make the konis fit, it was all the way around where the spring holder is welded on and where the brake line holder is welded.
So now I'm a bit unsur on how I should progress from here.
My AAS struts have been grinded, sandblasted and rust have been welded, they have also been primerd (paintgun) and the got 3 layers of top-coat by brush.
My non-AAS have been cut open and grinded on the inside so the konis fit. They do not have more than a few spots of surface rust so the will need grinding, minor sandblasting, primer (paintgun) and topcoat (brush).
Any recommendations?