I am 6'4" and race a SRF.  In reading the GCR it says the helmet must be 2" below the roll bar but it also says something about drawing a line from the top of the roll bar to the front structure and the helmet must be 2" below this line.  My helmet is 2" below the roll bar but is not 2" below a string stretched between the top of the roll bar and the front structure just in front of the steering wheel.  Am I legal?

Thanks for any help.