No I Haven't... (on the indomethacin ). But with a CH it is "better" to start at onset, but there have been times (like now) that my CH's are not as intense and sometimes very short, so if it is like a KIP 4, I will try to ride it out, but if it hit's 45 minutes or so, I will throw in the towel, because then I know it might be one of those 3 hour jobs.
But I can get on the O2 with a KIP 9, and it will stop it, it's just not as quick if I don't start at first sign. But I am speaking for myself here :).. I imagine it may vary by person.
I may be wrong, but it was my impression that Chronic Cluster sufferers even got breaks between CH's, just not real breaks in the cycle... And BOY will I be told if I am off base :).... And if that "is" the case (not sure again), then I would be thinking more on the HC like you said.