Trouble with cutter compensation in LinuxCNC

Using Fusion360 for CAD/CAM and that has been working fine.  For some high accuracy parts I would like to adjust cutter compensation in LinuxCNC rather than what I do now - go back and adjust in CAM and repost and reload on mill.  To test out the work flow I set up a simple block with a 1/2" hole cut by spiraling in a 1/4" end mill.  Looks good in CAM simulation.  If I select compensation "in control" I get "Arc move in concave corner cannot be reached by the tool without gouging" erro when loading and it doesn't load the file.  If I select compensation "wear" (which would be preferred as I could just enter the correction rather than the corrected tool radius) I get "Length of cutter compensation entry move is not greater than the tool radius " when loading the gcode file and doesn't load.  I tried changing lead in and don't know how to fix the errors - it's not clear what to do to eliminate the error.  Likely unrelated but I also noted that the Axis UI shows the new file name at the top even though it didn't load the file - I am running a very old version of LinuxCNC so perhaps that has been fixed. 

Have you had a look at chapter 4 here:

linuxcnc.org/docs/html/gcode/tool-compensation.html

Yes. Several times. Not saying I totally understand it all - I don't - but I get the basic ideas - I think.