This is how we did it.

First get a flat piece of board (wood/ceramic). Cut a hole in the board so that the monoblock hooks can fit in and the end of the monoblock is near the end. Lay it down flat and then use a wood clamp to clamp the monoblock tight to the board tight. The muzzle should just be over the other end of the board so that you can access the torx screw on the barrel cap whilst it is pinned down. Next insert two, 1.5mm spaces under each barrel. Slightly loosen the torx screw. The split will open and allow the barrels twist. Now clamp each barrel really tight to board with the spaces underneath. When everything is tight then retightened the torx screw on the barrel cap and the split will close and tighten on the left barrel. This will lock the left barrel relative to the right barrel.

Test fire and you should see that both bullets are level or very close to level. If not repeat with different spaces if required until they are level. I'd then consider putting Loctite on the screw so it never easily comes loose again.

Now if the barrels are crossing too early, you need to loosen the wedge in the centre. There are three 2mm allen key screws there. Loosen the two outer ones first then with only 1/8 of a turn slowly undo until you get the barrels crossing at the regulated distance.

I'd like to post the regulation at 100m but I don't know how to post pictures on this forum.

cheers chuck.