Yes, Pebbles', I tried "contributing" at the FB group, and found the mixture of assertive opinion and actual knowledge to be something I couldn't handle. It serves a valuable purpose, though. There are least three people there who used to be substantial contributors here who have found very substantial relief with DALT, while on the other hand some here did not get relief from DALT.
Other things for Tim:
Yes, D3! https://clusterbusters.org/forums/topic/1308-d3-regimen/
Some people find that sleeping more upright -- in a recliner or even at a table with your head on pillows -- helps with nighttime attacks.
An energy shot such as 5-Hour Energy, drunk at the first sign of an attack can reduce or even abort an attack. Many people prefer them icy cold.
You might want to take more melatonin. Some people go as high as 30mg. It's quite a cocktail you're taking at night, so I suppose you have to be careful about what you add to it.
Generally, 12mg/day of Imitrex is considered a "safe" dose. But it has side effects, for sure, and there is research showing that sumatriptans cause rebound headaches and extend cycles. Oxygen is your way out, as we have said.
I don't think the Xanax is helping with your attacks. Many people have found that skullcap is more soothing and less harsh than Xanax. You can find it as homeopathic drops or as a tea.
You might be taking the propranolol for some other condition. I don't think that beta blockers like that are as effective for CH as calcium channel blockers such as verapamil, though both treat hypertension.
The darn thing about lithium is that coming off it causes rebound attacks for many people. That's one reason why it is mainly recommended for people with chronic CH. I'd really consider trying the oxygen, D3, and maybe verap before stepping up the lithium.