I would like to say, I don't think this is better than than traditional methods, just different . It is a more efficient way to get a smooth edge, in a shop environment, where I might have to hone 20 razors in an afternoon.

Two bevel honing isn't really very complicated. The idea is that you hone a razor with your finish hone using traditional techniques. Then, you add a couple layers of tape to the back. Then, hone it very lightly once again, with your finish hone. The tape increases the honing bevel angle by a couple of degrees, giving the finish hone a fresh edge to work on.

The secondary bevel created is extremely fine. If you can see it with less than 200x, you are over-doing it. It is so fine, that if you were to go back to one piece of tape and a 8000 grit hone, you could remove it in less than ten strokes.

In fact, this secondary bevel is so fine that  the edge of the blade is still effected by normal stropping, without tape.  I use three layers of tape to establish the secondary bevel and lap with a balsa bench hone charged with chromuim oxide. Atter that, I take off all the tape and strop on a clean horsehide hanging strop.

When I started looking at the Feather brand DE blades at 200x, I noticed three distinct bevels. I built a laser angle measuring gizmo to check what the actual angles were. To my surprise the final angle was between 20 and 21 degrees. The Feather Professional straight blades were 25 degrees.

Most traditionally sharpened straight razors are honed to 15 to 17 degrees. That got me thinking that a little more obtuse angle, as a final step, might help give me the smoothness I was looking for. My razors are ground to have a 15 degree bevel with one piece of tape on the back. Depending on the width of the razor, three total pieces of tape will form a final honing bevel between 16.5 and 18 degrees.

Below is a photo of the Feather Pro. straight edge at 200x. The final bevel here is 25 degrees. You can compare this to the photos of the honed edges and bevels elsewhere on my web site.