You could offset the center line to each side at 1/2 the desired side width & set
the pline width to the desired width thereby eliminating the need for a hatch.
This would mean that you end up with two polylines. How does that sound?
Good for me , I did dot know how to handle it by (setvar 'plinewid nn) been nn the desired width .
Thanks , I learn my new thing of the day.
I can rest until tomorrow.
Gabriel