I needed to simulate a routing in a model (I don't have the routing module), so I drew 3D sketches in the context to create my pipes (virtual components).
I was confronted with the Cornelian choice: should I use the perpendicular stress between a segment and a face or normal to the face?
As a corollary, how do we reverse the direction of the segment once it is perpendicular?
The perpendicular constraint and "Normal" are the same thing in your case, I have never used "Normal" because I don't see the use of it.
As for the direction, I've always had problems with 3D sketches which I find quite limited. When I wanted to reverse the direction set with a dimension, I put this dimension in piloted and manually reversed the direction in the graphic area and then I put this dimension back in piloting because no possibility of reversal, at least as far as I know!