That makes more sense, although I can't say that I've ever had a problem with them twisting. The main issue I have is lining them up vertical in the first place, I can never work out how you can tell if a caliper is nominally vertical given that they also have a centering screw that can adjust the pads left or right.
No, so the caliper itself is nominally vertical. Since there's an adjustment screw you can get the pads evenly spaced off the rim even if the caliper is rotated off-vertical, so I'm never sure.
That makes more sense, although I can't say that I've ever had a problem with them twisting. The main issue I have is lining them up vertical in the first place, I can never work out how you can tell if a caliper is nominally vertical given that they also have a centering screw that can adjust the pads left or right.