I use flat diamond stones for most of my sharpening. They cut reasonably quickly and stay flat. No oil needed.

You have to remove metal to really re-sharpen. Hones re-shape the edge, but eventually you have to remove some metal. It takes a little practice to get accurate and consistent, but it isn't too hard. Always watch the point, it is easy to round off the point.

The various guided sharpeners make it much easier, but those are not cheap.

Does Randall have a shop specified sharpening angle? Does it vary by knife model. And, if anyone knows and can answer, please say whether you mean an inclusive angle (the angle formed by the two bevels) or an exclusive angle (the angle between the bevel and an imaginery center line).

I believe the paperwork that comes with a Randall specifies the angle.
They recommend 20 degrees.
I'd say use a white ceramic rod and the a steel hone rod rather than removing material that the diamond would unless the edge is really poor. Just my $0.02!

I guess I'm not smart enough to answer that question, but I sharpen at 17-20 degrees and do not use diamond sharpeners...(although)...a diamond "EZE-Lap" sharpening steel comes in the tube pouch and on my longer (4 5/8") Stanaback Special..."BUT"...it is intended for a quick and convenient touch-up method in the field & not as a steady diet.
Hope this helps,
Capt. Chris

For a long time I used a Norton bench set almost identical to the ones used in the RMK shop, they have a metal base mine is plastic. Nowadays I highly recommend Work Sharp products as they are extremely effective and very reasonable. Many products like the field sharpener are available locally.

I also use the 3-stone Randall, shop-preferred, Norton rig! Most excellent!
Stay Sharp,
Capt. Chris

A couple of days ago the unexpected happened. About 1.5 weeks ago, a friend gave me a Fox Vulpis pocket knife with M390. I used it and it finally got dull. Moreover, he became dull at a fairly simple task - sharpening a bunch of pencils for a friend's children while I was visiting him. Lol. At first I tried Arkansas, since the dullness was slight - it had the opposite effect, it stopped cutting altogether. I tried a ceramic triangular rod from Lansky - no effect. I went to Norton Crystalon Fine, he sharpened it, but the edge was rough. I switched to Fine India, the results got better, then I switched to Arkansas and again the knife stopped cutting and became very dull. That is, it seems to be sharp, but if you need to cut something like vegetables or meat, then it slides along the surface. An internet search brought me to this site. A guy with an electron microscope sharpens knives and looks at what influences sharpness and subsequent dullness. Perhaps this will be interesting to someone:

https://scienceofsharp.com/

After reading everything and thinking, I came to the conclusion that this steel is hardened very hard and dull due to the fact that when moving from India to Arkansas, I cannot maintain an even angle and lateral pressure spoils the base of the cutting edge and it falls off already in the process sharpening. As a result, I again came to what the Captain described at the very beginning - need to keep a constant angle

Then I took Fine India again, a black marker, so I could see where the metal was being removed, and sharpened the knife, trying to do it with very little pressure. As a result, the knife is very sharp. I don't see the point in switching to smaller stones. If I had a Norton 313 in the first place, I would have saved a lot of time

Along the way, I also bought a rather unusual diamond plate; it is made of bronze or brass and the diamond is distributed inside it evenly throughout its entire volume. It sharpens somewhat rougher than India, very similar to Crystalon Fine. Together they are a great couple