Griff, for trackdays it is 500mm from the can, that's what the twig on the end of the meter was for.
In theory if it was ok at CP and BH you should be ok, but both those meets were in conditions which would have helped reduce the noise - eg relatively humid. I reckon the only humid place this weekend will be inside leathers......
Paul
15th year in DD #68 and getting slower by the year
1199, SS800 & 620SSie DD racer