with a new threaded headset in hand, I thought of asking about technique people have for not marring the top locknut. It is difficult to avoid at least rounding a couple corners a bit during the final tightening because of the spring in the adjustable wrench. I figure this is either that my wrench of worn out or I am being heavy-handed.

My technique usually consists of adjusting the headset a bit too tight, then backing out incrementally either until the bearing seems right or it becomes too loose, in which case I retighten to the last increment and call it good. In short, this is a good number of cinching, providing ample opportunity for trauma to the locknut.

To address this I actually bought a non-adjustable 32mm wrench, but it turned out to be a bit wide enough to reliably round corners. My current wrench is 12" with jaws that open to 33mm and until now because of its heft, I have only thought of trying another 15" that may very well have less spring.