er,
I know what you may be going through at work, etc. My advice is do get your MRI to rule out anything else that may be possibly wrong in your head. Personally, I would not wait on the neuro to prescribe o2 as this may be too long of a delay for appt, time for insurance to hopefully approve, o2 provider to deliver, etc. Chances are you will not get o2 approved without a battle and chances are if you do get it approved, the flow rate and mask will not be what you need.
Sad but true, you will need to be your own advocate for proper CH treatment. Neuros are ignorant and insurance co's don't recognize effective treatment.
Knowledge is power and this website is the best resource in the world about CH's. Most of us have had to educate our neurologists and battle with insurance co's for prescription approvals.
There are several relevant threads of many posts you should consider reading based on your inquiries.
One thread regarding your inquiry of Verapamil that will be helpful is titled "Verapamil Dosage"...lengthy but offers neurological literature to print and take to your neurologist to get on a therapeutic dosage if that is what you and your neuro believe is best for you. This thread offers personal experiences with trial/error of dosages and stories of battles with neuros to approve high dosages, etc. This thread is listed under the "Medications/Treatments" board.
"Oxygen info"-yellow tab, left side of your screen. Plenty of info here about how to effectively obtain medical o2 prescriptions, how to obtain welders o2 same day, flow rates, regulator types, connection sizes, non-rebreather masks, tank sizes for home, tank sizes for work and tank sizes for your car, how to hyperventilate properly, etc.
Welders o2 will most likely be your fastest way to get o2, a regulator from Harbor Freight or the welders supply store, a NRB (non-rebreather mask from the ch.com store-yellow tab/left side of your screen.
Lastly, FMLA may/not be applicable to you and your workplace; you may want to check into this should you not be able to work. See the thread titled "Missing work" found under the board "Cluster Specific." Also, there is a very well written "letter to employer" under the "Getting to know you" board for you to print should you feel the need.
Lots to read here on this website, and we do understand, so please don't hesitate to vent when you need, ask questions, etc, you are not alone and we are your best support team here to help each other.

-Gregg in Las Vegas