I am trying to sketch a (raclette) chees loaf. I am using follow me. No matter how I try: is just cannot fill surface “A” uniformly. This stops me from filling surface “B” with another color:
OK, using what you drew as a starting point, I created a profile/cross section and a circle for a Follow Me path. Note that I am working centered on the model origin so I have a fixed center reference.
Erase the the unwanted stuff. Use Offset on the flat cut face to outline of the wax or whatever it is. Note that the edges are not the thick profile edges as you showed. This thin non-profile edges indicate that the edges split the face into two regions.
I suspect you started with a semi circle for the path and a profile for Follow Me. Something like this. Here I’ve used a default 12-sided arc and the profile is on axis. You can see that the first and last segments in the arc are not perpendicular to the base line which is on axis, too.
When Follow Me runs it projects the profile to perpendicular to the first segment and the extrusion ends perpendicular to the last segment. You can see here how the end of the extrusion is not oriented on axis.
In at least one of your tries, you used 72 sides for the semi-circle which creates a smoother extrusion but the first segment is still not perpendicular to the what will be the cut face of the cheese.