Of course, welding O2 is always an option, maybe even as a backup or supplemental system for what they give you (for example, so you go through the Es less quickly and maybe they stop hassling you about a concentrator, and meanwhile you're building that relationship with the delivery person or some executive at the company).
I have to fight with my oxygen company often as well. I keep calling and make my way up from call center to local manager and now I have the reginal managers number and we are on a first name basis.. Don't give up and call until you get what you need. I don't know your situation but I found that paying out of pocket in cheaper for me and also better for the oxygen company because they do not have to deal with the insurance approvals and things like that. I just pay my bill on time and that keeps them happy. Tank supplies at my distribution center get depleted and I have issues getting the M size tanks but getting to know the delivery driver and being kind to him went a long way with me building up a nice stash of "extra" tanks. A cold bottle of water, fresh veggies from the garden or a few bucks goes a long way with the delivery person!
Find a way to get someone on the phone that is willing to listen to you and work to get you the tanks you need. as long as they are getting paid for each tank what do they care how many you are using. The supermarket doesn't tell you you can not but 10 gallons of milk a week do they? They just want to sell it and make the profit!
Dont take no for an answer and move up the chain of command until you get it. I am not in your area so I do not have a suggestion for what company would be better for you sorry.
This might help you prepare for your neurologist appointment (and some sections might help you cope while you are waiting). https://clusterbusters.org/forums/topic/6213-basic-non-busting-information/
Do everything you can to get oxygen. Even though it is the #1 recommended abortive, many neurologists don't prescribe it (almost never for a good reason -- they just don't).
And you probably should start the D3 regimen now (there's a link to it in the post I gave you in the first line up above).
I also get pain in the upper jaw below my eye like a tooth is being torn out. It will move around from my ear to upper and lower eye.
Welcome to the club.. Read up and ask as many questions as you can think of, We are all here to help each other and no matter what your feeling someone here has most likly dealt with it and may have a trick for you to make it just a little better.
....no particular place on head is definitive..... but anywhere the trigeminal nerve goes is a possible. my pain was a straight red hot poker from temple thru eye, into tooth..... ymmv