Combine tangent skim modes and shoulder modes

OpenLab CDS allows to configure tangent skim modes and shoulder modes separately. However, not all combinations produce equally useful results.

Recommended combinations of Shoulders mode and Tangent skim mode

Shoulders mode	Tangent skim mode
Drop * * Or any shoulder mode	Set skim height ratios to 0.0 to separate by drop line.
Gaussian	Gaussian
New Exponential	New Exponential
Tangential	Straight