That is a really detailed response.
Do read up about D3 and PM Batch is is very helpful with getting people started. It has a success rate of about 80%, so hopefully it will be right for you.
Not too surprised about topamax, I tried it for migraine prevention and hated it with mental fog, being lost for words, metallic taste in my mouth and tingling, so just about the full range of side effects. Whilst it seemed to be doing ok as a preventive, the side effects were too much. But others have tolerated it well.
For oxygen, we need pure oxygen, so the oxygen concentrator just doesn't work for most people at all. So it is a matter of using oxygen cylinders. Being sensible with looking after it makes it safe. Don't smoke or be near a naked flame when using it. After using it, don't go near a naked flame for say 10 min. Otherwise the main risk is dropping a cylinder on your toe or similar. Lots of people are reluctant to use it at first, but they are soon converted to how wonderful it is.
With energy drinks or coffee, these are not a first line abortive, but more a case of something is better than nothing or for low intensity CHs.
When you've got something that works well, i.e. imitrex injections, it can be very hard to try anything else when something else might not work and the result is a lot of pain from a CH. I think everyone will understand that. But using multiple imitrex injections per day isn't always a great idea either. Oxygen has the benefit that you can use it many, many times a day.
Verapamil is known to potentially cause issues with the PR interval on an ECG, which is why people using it should have an ECG every few months to look for the warning signs. Although you're the first person I've heard of to have hand such a serious reaction to it. It works very well for most people.
With botox a lot of the medical research studies have found that it is little better than a placebo for CH, although for migraine it can help people. So I'd not put too high a hope on it being a magic bullet.
Predisione tends to work very well as a preventive, but it is for short term use only, typically 7-10 days whilst another longer term preventive builds up.
Indomethacin doesn't tend to help with CH, so for it not to help isn't too surprising.
For the infusion cocktail, this might have been DHE.
Vvanse - doesn't seem to be too well reported as being useful for CH (Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

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As for diet, well some people have found possible triggers in some foods, but this seems to not be too common. If you find something is a trigger for you, then avoid it. Try to use a headache diary to see if you can identify triggers.
Water can help some people, either enough to ensure they are not dehydrated or for some, lots, but I don't think it is a great preventive for most people.
Hot / cold - this is interesting. Some people find getting too hot or exercise can bring on a CH and for others, a very hot shower can bring relief. Similarly ice packs or frozen peas can work wonders. If one of them helps, use it.
Interesting about the impact of digital screens, every so often someone will say they are a trigger for them, but it seems to not be a problem for most.
Acupuncture and chiropractic - seem to be useless for CH.
Stress is very interesting as a trigger for people. For some it is high pressure that is a trigger, for some low pressure and others the transition from one to another. For me, high pressure works as a preventive, with holidays and weekends being CH (and migraine) triggers.
Triptans can be a very useful means to abort CHs, with the injections or the nasal sprays working best by far.
Keep reading and asking questions....