Well, I've never been accused of varnishing my opinion very well. Learned long ago, better to get it out there, than hold it all back or wish you'd said your piece. Least you'll always know where I stand, sincerely.
....And that's why you're one of my favorite people on the internet. I had to jerk your chain on this one, particularly because I agree wholeheartedly with your assessment of most slow rust bluing processes.
Reading again through a book
Gunsmithing at Home by John Traister, I learned that the kind of bluing I did on this rifle is technically (or classically, at least) called "Hot water bluing", rather than the true slow rust bluing, so I have been mis-speaking of the process I decided to use on this rifle. The difference is more in the process than the chemicals. Hot water bluing requires the metal be as close to boiling water temperature as possible, and generally the metal is boiled just to heat it, then pulled out and as soon as the last bit flashes dry, the solution is applied exactly as you would if you were to do the slow process...except on the hot metal the rust forms instantly. Also, the metal is re-coated twice very quickly before returning to the boiling water to blacken for only two minutes or so (instead of 15 for the heavier growth of red rust from the slow method). Then the surface is carded (I use 4-0 steel wool because my soft carding brushes left a dull finish on test metal), the metal is boiled to heat it, and the process of applying three quick wipedowns with a dampened cotton ball is repeated.
I put seven coats on the barrel in about two hours not counting set-up or clean-up time. Most of the time spent is carding, especially if doing multiple small parts.
I've done "real" slow rust bluing before and found it ended up matte with a silvery hue, which is sort of the nature of the beast when pitting the metal and carding aggressively as you must with thicker rust. Comparing the durability with a file, after the finish "cures" for about a week, I can't tell any difference except the hot water method, using Mark Lee's Express blue (or brown with same method), can be made to look like that old Colt foot-deep blue. The blue is also repairable.
If I felt like getting an FFL I'd put out a shingle, but not quit my day job. This stuff is a labor of love and honestly even if I got good enough to charge for the work the going rate per hour is half that of a decent auto tech, with no chance to beat flat rate time to flag 60 or 100 hours in a 40-hour week. It would take me a couple of years just to pay for a real lathe, mill, stock duplicator, and tooling, and I'm almost out of trees
Seriously, if you want to try this yourself, the bluing part is easy as follow the short/sweet little instruction booklet from Mark Lee. What's NOT easy is the metal prep, that's the part you might as well hire a pro to do, particularly barrels.