I doubt that someone will do the ignition time tuning at 6000 RPM !, diffrent range of vehicles should run well atleast on 1200 RPM max. so tuning the time at these speeds will automatically tune it for other speeds.
for the 1200 RPM the frequency of spark #1 firing would be about 20 Hz (1/20= 50 mili seconds) . so if i turn the led on for 5 mili seconds it should be accepable cause there is 45 milisecond to another sprak. and also i doubt that a Xenon Flash light stays lightly lower than 5 mili second. consider the LED reaction time would be in micro seconds and it's being lengthed to 5 mili seconds .