For this particular tartan I would pleat to the red stripe since it is bordered on both sides by the same color, blue. The white stripe is bordered by two different colors, green and black. Nothing says you can't pleat to a stripe like this, but I think the back of the kilt looks much better when the pleats are consistent.

For what it's worth, I highly recommend 6yd knife pleated kilts in heavyweight tartan. Matt Newsome has made several of these for me and they are wonderful. These have all the benefits of the heavyweight tartan and retain the traditional look of a modern knife pleat kilt (each pleat is a little wider) but are so much better balanced and comfortable to wear.

Having sewn two home-made kilts, I would encourage you to save your pennies and have Matt sew this up for you. His craftsmanship is superb and the fit will be excellent. There are certain skills (kilt-making, surgery...) that come as a result of repeating the same techniques over and over. In my mind the trade-off between cost savings and the quality of the finished product leans to having the pros do it.

Best of luck either way!

Cordially,

David