That is exactly right. The type of tartan has a unique way in which it needed to be cut either for the pagris or as a badge backing. Brian L Davis has a nice chart explaining this in his book on page 119. This is for British units but I would think Canadian units would have followed suit to a certain extent. There may be some unit uniqueness here as well. I believe the 16th and 17th Battalions wore the same tartan in WWI but cut the tartan differently for badge backings ?? As a personal observation, it seems that many of the cuts would be done to show either St George's or St Andrew's cross.
Here are images of a couple of examples which illustrate how tartan backing is supplied by their respective Regiments. Note the alignment of the tartan.
Wow! that is a beautiful helmet Ypres! Thank you so much for sharing it with us!
I had no idea the triple-fold economy Woleseley was around that early (is it dated 1939?). The khaki wouldn't have matched the greenish Canadian KD, though I don't think I've ever seen any sun helmet that would...