Unlike Iride01, I adjust headsets with no play. Install it in the stand initially. Then put the bike on the floor. Hold the front brake and rock the bike back and forth to detect play. Hold the front wheel between my legs so I can use one hand on the wrench on the adjustable and the other hand on the wrench on the locknut. It's a good idea to adjust it too loose at first (locking the locknut) and then tightening the adjustment very slightly (again tightening the locknut). If it's still loose, tighten it again, still very slightly.