Actually I've done just that with a M3 specifically. What I've found is newer guys follow the instructions to a tee since they don't know any better. I oversee any prep work and do most of that myself since gunsmiths know little if anything about chemistry and lots can go wrong. Of course I always look at what came out of the tank last to make sure they have some clue and all is well with the setup so no I don't just drop stuff off on the porch with a sticky note on it, there is some diligence involved with everything I do. I'm not the total idiot I may appear to be?
I see some old guys, "major names in the industry" home brewing park solutions, not maintaining their tanks/ solutions, etc. and have long ago tossed the instructions and run by "feel or look". That's not how chemistry works. I was at another local guy last week and he was "re-doing" 15 guns that were parked by a guy that builds at least 150 parked guns a year. He's not the only one, I've seen lots of it over the years as well as finishes failing in the field months down the road. I'd love to park here myself, but the volume is too low and there are lots of guys close by set up that do good work for cheap, so I limit finishing here to what we can't get done elsewhere economically like hot bluing 60" 45# parts. Physically and chemically challenging in a t-shirt .
So how's this project going anyhow? Any new pics?