@Willy I'm very new here as well so would be inclined to put other people's advice ahead of my own but wanted to chime in.
I also have had nerve blocks in the past, but I also found a medication called Verapamil was really effective. It's a blood pressure med with very little side effects (constipation, can lower heart rate at high doses) and I was taking 2 x 240mg/day when I'm in my cluster period. Would still get some shadows but it has been the biggest help to me, you just need a prescription for it. Most people recommend getting the standard release, not the slow release, and I would take it for a few weeks until I felt like I'm free of cluster. It wasnt something that would abort a headache in progress, but after a few days taking it was like the inflammation got under control.
As I understand it though it's not effective for all CH sufferers but the fact you'd previously had success with the nerve blocks rang true for me so wanted to throw it out there. I'm ordering what I need for Batch's D3 vitamin regimen now so I can have 2 x lines of defence.