First off. Where did you get your PV?

and what do you mean by bar tacks? I only use those around the belt loop hole.

Most people sew the edge of each pleat from the top of the kilt about 1/3 of the way down.

If you want a nice 8 Yard traditional kilt you will want to cut out the backs of the pleats above the hip line, and sew in hair canvas. With less yardage you might be able to get away without interfacing by leaving the inside of the pleats intact.