I don't have a RSK, and I don't usually measure the edge angle when I sharpen a blade.
However it does depend on what the knife is cutting like.
If the edge is not biting well I reduce the angle, if it is dulling to fast I increase the angle.

Too fine of an edge either crumbles or folds depending on how hard the steel is, and too obtuse of an edge angle does not slice well.

The extremes would be the acute edge angle of a razor and the obtuse angle of a cold chisel.
You would never think of shaving with a cold chisel, or of driving a razor blade through a steel bar with a hammer.

A straight razor is about 15 degrees.
Most kitchen knives are between 20 and 25 degrees.
Most wood carving and general use knives are 25 to 35 degrees.
A cold chisel is about 45 degrees.