Hello,
For me no hard alcohol. I take 3 or 4 shots and a cluster starts. I can drink beer (not during a cluster of course ). And I use it as a test to see is the cluster is really over. And can start lowering my verapamil regement. I've also had one triggered by lager or stout. I'm about 6 years in and it's taken a long time to get my triggers mapped out, seems I keep finding new ones.
So beer would not extend my cluster, but hard alcohol would probably start a new one. As always every CH is different.
good luck,
rkeck9999