It'll really depend on the Tartan sett. If it's a short set, say 6 incehs, or you can use a half-sett to the stripe, it could work. I have a Macdonald of Glengarry 4-yarder from B&S, and the pleating looks good - but the shallower pleats don't seem to hold the crease well, especially at the first and reverse pleats. If you were to make those deeper, and do the rest shallow, you'd probably be OK.

alternatively, wait and save for the rest of the cloth you need for the 8-yarder. It would be worth it.