Yes - this is definitely symmetrical. The number of threads in a stripe isn't the determining factor - it's the fact that you can find a place in the tartan (a pivot) where you can fold the tartan in half and it's a mirror image on the two sides. You can do that with this tartan, so it's symmetrical.

The large # of small stripes only becomes an issue for pleating to the sett if the pleats need to taper dramatically between the hips and waist. Lots of taper makes it tricky to place the pleats so that you don't lose prominent stripes between the hips and waist. Since you don't have that much waist-hip differential, though, it's a far easier job.

Some tartan just doesn't pleat well to the stripe. And, frankly, it typically isn't clear until you have tartan in hand, pin up a test pleating, and stand back about 20 feet. That's what I always do.