Hi Celtic! Welcome to the club! Have you read the blue banner at the top of this page? It will give you a lot of basic info.
I would not worry about the O2 usage. The main thing is to have your system optimized with high flow pure O2 at 15 to 25LPM and a non-rebreather mask. The Cluster mask is what most of us use. You have to work at your breathing, not just breathe. As in exhale with force, till you wheeze a bit, then inhale deeply. hold a few seconds and repeat. You can begin this on your way to the O2. With nocturnal hits, you want to get there ASAP too. You will find your own pace and way for each hit. It likely will not be the same for each, so try different paces and when one begins to ease the pain, stick with that method for that hit.
May will down a caffeine drink with the O2 or just prior. As in hit the fridge, grab it and go. You can chug as you go. You must stay on about 5 or 10 minutes after all the pain is gone. Otherwise, you risk the hit returning. 'Post' breathing is very important. For daytime hits, do the same. On occasion, you may find that the caffeine is sufficient and O2 is not needed.
Pred is a bridging med that you take for a week or 3 and your Verap kicks in for lasting relief. Pred is not a safe drug to take for a long time. It causes your hips and maybe shoulders to lose the ball part of the joint - it dies. Then you need a hip replacement. So, use, but sparingly.
Verapamil is one that CHers tend to take very high doses of compared to other patients. As in up to about 960mg/day. Some can't take those levels of it due to low blood pressure. It is great for many when it works.
For shadows, use ginger: tea, candy, etc. It kills them. As will caffeine. But caffeine gets tiring.
There is a lot more to share, but this will get you going!!
ATB !