Hey there Ray

It's good that you got a successful diagnosis for the alarm clock headaches. Some of us were undiagnosed for a decade or more.

Sumatriptan does work remarkably well to abort cluster headaches. The only problem is the delivery method. As you've noticed,  it takes the tablet 15-20 minutes to kick in if you're lucky. If you're not, it may take 45 minutes to an hour, or even sit in the stomach without being absorbed until after the attack finishes on its own.

Consider getting oxygen - it aborts attacks quickly and is about as safe as any treatment can be (it's oxygen after all). It's the first line abortive for the majority of experienced clusterheads.

Since sumatriptan has proven to work, see if you can get your hands on the injection (first choice) or the nasal spray (distant second). They both work faster than tablets and aren't affected by the nausea which some people get with severe CH attacks.