Interesting Miilos. Of course many of us use coffee or an Energy Drink for a Cluster, so I do get the point that sometimes too much coffee is required. It just leaves one feeling jittery and 'not right'. How many times a day are you needing caffeine? Can you tell us where you are located?
Are you getting the pain only on one side or are you getting both? Did the tests include a MRI? How did your doctor come to the diagnosis of Vasodilation Headache? I normally see that with reference to a particular medication, not a stand alone disease. Not that it isn't there! It very well could be and I just have not heard of it.
Here are some medications associated with Vascular Dilation Headaches:
Many drugs can cause vascular headaches by inducing vasodilation. These include antihistamines, sympathomimetic agents, amyl nitrate, nitroglycerin, nicotinic acid, hydralazine, prazosin, pentoxifylline, cyclandelate, nifedipine, perhexiline, theophylline, aminophylline, terbutaline, and dipyridamole.
This is the D3 Regimen. The original and it contains fewer vitamins to take, as it is not so focused on anti-inflammatory and histamine. https://vitamindwiki.com/tiki-download_wiki_attachment.php?attId=7708 It has helped many a cluster-head get out of pain and stay there for extended times. There is a more extensive one as well if this does not work.
Are you taking any other medication that would affect your head? Like for heart issues or similar??
Next question: If you are only getting them a 'few times' a month, then why the concern over the caffeine? Does each headache require several cups of coffee to keep it at bay?