Oh, I most certainly do, I think I've tried about every method, lol. R Nicholls mags I've actually seen just have a steel pin glued into the bottom of the floorplate, how legal that is I'm not sure.
There are various methods for indenting the magazine tube but with the Sauer mags you have to be careful because the spot welds on the back can split if you apply too much pressure. One method I've seen is just to indent each edge of the magazine so the follower can't move down, but it's easy to defeat by grinding out the dents.
The best method for mucking about with the tube was unfortunately by far the most complicated and I suspect you will need the help of a well-equipped gunsmith to do it, I did in the end, but I was going through Customs and I needed it to be permanent beyond any shadow of doubt.
Measure off some small thin, flat pieces of metal that will act as flanges inside the tube. Work out exactly where they've got to go by putting ten inert rounds in and putting the follower in.
Epoxy the pieces of metal in. Drill the tube and drill through the flanges (you may need to drill the holes in the flanges first before you glue them in, depends on how long you want to wait for the epoxy to set). Get some decent thick and hard steel wire, cut some very short lengths and spot weld them to the flanges and then run them through the holes, and then spot weld it in place to the magazine body. Mine used four holes to hold each corner of the flange.
Then grind off the ends of the wires that protrude from the magazine body. (You have to do the same to any sticking out of the flanges before you put them in).
If you do it right you can still disassemble the magazines completely, you can get the followers out by tilting them, and its as permanent as it gets.
I suppose you could drill out the wire and pry off the flanges but if you do it right it would be very messy to remove them, because the spot weld would make a mess of the tube if you cut it out.
Other ones I've seen here aren't as effective as this method, they usually involve the floorplate being pinned or welded on after a dowel is put inside, which sucks.