Less distance for A, slower steering, less chance of headshake.
More distance for A, the opposite.
On my o7, have 6mm from top of trip clamp to top of fork leg (not including fork cap).
Mine was nervous and a hair headshaky this morning running the ski resort road, I'm gonna slow steering down. My '07 has a circumferential groove on the fork tube about 4mm from end, gonna adjust to there.