as it’s very very easy to break the bars
No it isn’t. People need to get away from thinking carbon is swiss cheese. Carbon bars in particular are very tough, and they don’t just snap with a small scratch in the surface lacquer / paint.
As for the above Superstar bar ends, that’s rubbish. The grub screw pushes a metal band inwards to tighten. Nothing digs into the bar. It’s equivalent to tightening a strap around the bar, though on top of that the band tightens around the plastic grip, *not* the bar itself. I’ve used them for years and not a scratch on my Easton Havoc carbon bars from Superstar grips and those end caps. Plus they are end caps, not locks. They shouldn’t need to be that tight anyway. The locks are on the other end and they clamp the lock, not dig into the bar.
All that said, use carbon assembly paste on the bar before clamping anything to it. It reduces the torque required while retaining grip. Worth using even on aly bars.