Parkerizing and blueing are 2 completely different things, parkerizing is actually a trade name, in other words like Xerox became xeroxing, copying, black phosphating has become parkerizing.
Here in Los Angeles theres a place, "parkerizing of LA" that does great stuff, but you have to take your stuff to the back door, shipping, take a 12 pack of good mexican beer, corona or pacifico, and ask when they change the chemicals and then drop off the stuff and the 12 pack, if you go thru the office they have a BIG minimum charge, go thru the back door.
When they ask if you want it oiled say yes
If your not in LA the kits work good, there are 2 colors available, 1 is kinda green and is correct for pre 1946 harley davidsons, the other is blacker and looks better for non H-D's
I've done both my personal bikes and several others in either way. the loose rule of thumb for bikes is if the nut/bolt/washer was next to paint, it was parkerized, if it was next to bare metal, it was cadmium plated.
Heres the secret for the kit's that they don't mention in the instructions and is very important as told to me by a friend in the aero space plating industry, and once he told me it made a world of differance.
Follow the instructions, I did mine on a camp stove, but what you need to do is heat oil, I used motor oil, to the same temperature as the instructions have you heat the chemicals. my memory thinks 180f, then after you remove the parts from the chems, place them in the heated oil and let cool.
They come out bitchen
If you enter your car/truck/bike in a show, light oiling of the parts/bolts whatever makes them look great, if you neglect them they will eventually fade, but oiling makes them look good again, they shouldn't rust unless you seriously neglect them or leave them outside forever. It's a great preservative. My bikes win awards in antique motorcyle club of America shows by the way, I love parkerizing.
If you would like to see photos, contact me personally i will send photo's of parts done professionally and by myself to see the differance, the parts done by the pro's, the day they cahnged chems are by far thee best, but the ones I did are more than acceptable
sorry I went on about this but i do have experience and thats what you asked for !!!
Ciao for now