...you can only strip your HOG if you have taken their class which is a significant expense as you need to be a tech diver and then you need to take the class
You can buy HOG Service Kits from Diverightinscuba on the web. You can strip your HOG if you know how to service a reg. The class is helpful if you are not familiar with Apeks regs. The "restrictions" on class attendance are primarily designed to discourage the dangerous amateur do-it-yourselfer. But you can find HOG dealers that will teach you with just a Nitrox card and a true desire to keep your regs well-serviced.
...My LDS stopped servicing the regs that they are not trained in servicing a couple of years ago.
If you can't find a shop to service your gear, find a mentor and buy Harlow and Wolfinger and learn how to do it yourself.
If that is not something you're comfortable with, you will find just as many trustworthy and skilled home-regulator-maintenance divers in your area as you will at many shops. Doing a few regs in the shop with Joe looking over your shoulder and then going to the factory seminar does not a regulator technician make. Look around. The skills are in your community. The parts are on EBay. Go for quality service - maybe at your LDS, maybe not. If not, there is someone in your town who will give you great service.
Of course, we'll get a liability post in here next...
And my reply is, my "skilled" and insured service tech billed me for a "torn" diaphragm in my D-350. I took it to him to see how he'd do. Tearing the SP D-series diaphragms is a common error with unskilled techs. Cracking effort was suboptimal, though "within specs". Last time I'll experiment, but it was worth it to gauge the local quality. I take care of my own gear.