I am sooooooo glad you brought this up.
Right handed asymmetry means that the knife's left side bevel (holding the knife by the handle) is sharpened wider than the knife's right side bevel. Unsurprisingly, left handed asymmetry results from the reverse.
As a practical matter, asymmetry usually means the apex of the bevels (i.e., the edge) is NOT on the center line. Almost all knives sharpened on both sides are profiled with the same edge angle on each side, and even more of them should be.
In engineer speak: The choice of edge angle and symmetry is all about balancing stress and fatigue against wedging within the context of (material) strengh and toughness. You want the part of the knife just above the actual edge to be as thin as possible while robust enough to stay "in true" and not tear or chip.
Greater symmetry translates to greater width (and stress resistance) just above the edge. If you're going to steel (and you should) as part of maintenance, you need a enough symmetry to prevent a stess line from beginning at the bevel shoulder on the short side, running through the center of the knife to at an oblique angle. If the knife is too thin at the short side shoulder bevel, the alloy will fatigue enough to make it more likely to bend -- or even tear. If this is unclear, we can go into more detail in a subsequent post.
66.6/33.3 (aka 2:1) is a sort of max asymmetry if a rod hone will be in the picture. Eyeballing bevel proportions isn't that exact, so shoot for 60/40. Your knife will still be unbelievably sharp compared to whatever you used before.
If you're not going to steel, but "retouch" on your EP everytime the knife gets slightly out of true, you should sharpen to the greatest degree of asymmetry the knife can hold. I'm not sure how far you can push the VG. 80/20 anyway. I have a friend who sharpened his to a near chisel (call it 90/10) for restaurant use. It was very sharp, but kind of marginal about making it all the through a service. He'd recommend it, but I don't.
You'll want to use The Magic Marker Trick when you first start grinding in asymmetry, so you can actually see the bevel shoulders and compare them to one another. If nothing else, this should reinforce the ideas that you're eyeballing symmetry by rough proportion, as well as the importance of keeping a smooth shoulder parallel to the intended edge.
By the way, the "included angle" is determined by adding the values of the edge angles. A 15* edge angle on each side means an 30* included angle.
The "default" edge angle for most sharpeners doing Japanese knives is 15*. Better is to sharpen the most acute angles the knife will hold without the edge collapsing too frequently. In the case of the VG, that's probably just a skosh more than 10*. It's something you can play around with for awhile. If you don't want to fool with it, split the difference and set the EP as close as you can get to halving the difference between the 10* and 15* marks as you can.
After four decades, I'm still messing with my Sabatiers.
~60/40 righty at ~12.5* (both sides) is a good default. Alternatively, try 10*, also at 60/40. If that doesn't hold up long enough for you, sharpen a 15* "primary bevel" on top. You might really like the way a double bevel combines thinness with durability.
PS. Since the question is probably going begging: I am not a trained engineer. But have some small background in physics, more of one in math, and picked up a little materials science on the street corner over the years.