>though the mechanic at Sigma did show me a tip
Do tell…
On the a SuperSix Evo seatpost – was the trick tighten the first 3 to 4 nm pushing seatpost towards rear of bike, then pull it forward for the final tightening? Worked for me.
Very similar to this. Set post height and torque bolt to spec. Following this push down on nose and tail of saddle alternately (so you’re using the saddle to rock the seatpost back and forth (not that this will be visible) – he used a fair amount of force). Do this then re-torque the wedge bolt, repeat again to be sure.
He was using a digital torque wrench and it was quite clear the bolt torque was less after the initial ‘rocking’, the reason being that the wedge won’t settle in a 100% even/final position if it is just tightened straight up, the movement of the post helps it settle into a neutral clamping position (if this makes sense).
Plenty of miles since it was done and post is solid and silent.