I gave a source for a free download for the Sherwood (and others), I'd talk to Jim Lapenta about the Hog. There is a lot of DIY reg techs on this board and others, so it would be a matter of time before you could find the information for little or nothing.
With some machanical inclination, patience, basic tools, and the desire to to service your own reg, I believe most divers that want to, can learn to service their own regs. If you have to buy a toolkit because you have no tools, you are probably not a good canidate. There are a lot of special tools and instruments that are available, however a lot of them just make things easier, only a few are actually necessary to do the job on certain regs.
I started successfully repairing some old regs without a manual. I've been a mechanic on a variety of equipment over the years, so I have tools and background to work on what shows up so I have a head start. With frogkick.dk, and the advice from other Scubaboard regulars, I find repairing regs much easier now.
Over the years, I have spent a a few hundred on special tools, but it was when I had the $ and couldn't make the tool myself, or my DIY tool needed an upgrade.
If you want to service your own gear you will find a way, if not then don't. That is the balance. Just tossing money at an issue rarely solves anything.
Bob
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I may be old, but I'm not dead yet.