Does anyone have a good trick/technique for controlling lines projected on a variable surface?  I am trying to keep the lines parallel and at a fixed distance (.42" is my goal).  Picture a recess for a label that has a fixed height.  I have tried using a split line (model attached) with ungood results.  A wrap won't work on a lofted surface.  Best I can come up with is just fudging the sketch for the split line until I get something approximately right.  Maybe even more difficult, once i get lines projected well, I need to use them for an extruded cut normal to all the surfaces involved.  Maybe can't be done?  Thanks.