Need a Dbl check on my measurements

[meinfs]

Yes, but what of the 2" pleat depth ? is that too shallow?

2" pleat depth is ok. 3/4" to ~1" pleat size ok.

My thoughts: I find that it's easier to pleat tartans than solid self-color fabric because the lines are already there in the fabric! (With solids you have to draw them straight and square.)
This is my workflow for pleating to stripe: I first look at the sett and the lines around the prominent stripe that I plan to pleat to and then from there decide on the edges of the pleat to put the creases into. Once you've decided on the the pleat appearance and therefore its size, then use that pleat size and the pleat section @ hips to calculate how many pleats will fit your pleat section @ hips (in your case 24"), give or take. A similar tartan for me (stewart gray), I ended up having about 30-31 pleats. For my first kilt (handsewn) I had 21-pleats of 1" per pleat.

I hope I'm making sense. Good luck! Looking forward to seeing your creation.