A few months ago I attended one of Richard's classes and after a few days the light bulb started to turn on in my head, and the work became straightforward, accurate and even pretty.... or try to find someone else with lots of experience reconditioning machinery in real life, who will take you under his wing and teach you right. Warning, there are a LOT of wannabe experts...
That would be fantastic. perhaps one day I'll be lucky enough and, yeah, there's lots of crap on yt and other sources and as for learning it on your own, not sure what to really add to what you and Richard have already said about it.