Hi
So far I haven't though about relations between the angle of the primary bevel and the secondary. I'w alwayse just made a primary angle that fit my taste and the blade.
I ususally do a 25? secondary bevel.
I did try a 20? on 2 knives that made the secondary bevel look quite large on the blade, since the primary bevel were shallow to start with.
Is there some rule of thumb on some angles that go well together?
Does it have any influence on the cutting capabilites on the knife?