Can't comment on four or less blades but six can take a while.
The Chinook has interactions between the forward and aft heads so the rotortuner box's adjustments are fairly academic. Back to the books and course notes if it has been a while between rotortunes.
A good rotortune can take 3-4 flights of 45 minutes each, dependent upon the reason for the rotortune. Blade and head changes take the longest and have been known to take upwards of a week with 3 flights a day.
What fun we used to have........
