I don't know a lot about methlypred, so I can only say that those dosages sound low, and I feel certain they're much too frequent. Here's what one expert says about dosage and use: "Corticosteroids in the form of prednisone 1 mg/Kg up to 60 mg for four days tapering the dose over
three weeks is a well accepted short-term preventive approach. It often stops the cluster period, and should be used no more than once a year to avoid aseptic necrosis." https://clusterbusters.org/wp-content/uploads/2014/03/GoadsbyClusterTreatment.pd
I don't know of a medical O2 tank that is 2000 liters, but that's a big one (M size, I guess), which is good. I've written a bunch about O2 use at this file (same as I linked before), so maybe you can take a look there and see whether you have further questions. https://clusterbusters.org/forums/topic/6213-basic-non-busting-information/ 10/15 lpm might be fine, or it might not be enough. Your mask might be fine (with some modifications), or you might want to try upgrading to the "Cluster O2 kit." Your breathing strategy might be fine, or you might want to try something different. All addressed in there. I'd also note (quoting from there): "Some people have observed that for some reason when the O2 level in their tank is “low,” the O2 doesn’t work as effectively for aborting, or might not work at all. “Low” in some cases can be as much as a third of a tank remaining. Something to be aware of." Batch has also posted data about how it can take a while at first for O2 use to become fully effective, so that might be a "normal" O2 issue you're having. Another tip for using O2 that might or might not be in there is to look down toward your feet as you use it. Don't ask me . . . but many people find that it helps. With a proper system and techniques, you ought to be getting aborts in less than 10 minutes.
Also in that doc are some things people can do when they don't have O2. There are a bunch of them, with caffeine or energy drinks/shots the most common. Also, Benadryl, melatonin, "brain freeze," and some other possibilities. I just don't know what you want to do with the baby in there.
I really don't know why the Maxalt and Cambia have those CH exceptions so prominently stated. One of these days I might look into that.
You can also look things up using the search bar at the top right each page. Just a good thing to know about.