I was always told that you rolled your finger away from the fipple to half-hole every note. The reasoning is that on every other note if you roll it towards the fipple the the next finger will get in the way. It seems logical to do the same for C natural, just for consistency.
I can play a full chromatic scale with the technique, it’s easy once you get used to it.
I started using it for jigs with BCB in them. Trip to the Cottage being a case in point. Just flex the last joint to raise the tip, rest of finger rests on the barrel undisturbed. Otherwise roll down I guess.
Aybody half hole C every time? I think Joannie Madden does.