Brad,
I actually haven't ever seen a Grant tartan kilt pleated to stripe. I think it might look all right pleated to one of the light blue stripes. One of the dark blue stripes might work too. Personally, I'd go with pleated to sett.

As for what hue to go with, definitely go with your first inclination. When I first got my kilt I had no love for the Grant tartan in ancient colours. It was too orange for my liking, but over time it has grown on me. I'm toying with the idea of getting a second kilt made in either the ancient Grant Hunting or Grant muted tartan. The nice thing about the ancient Grant is that it's more subdued than the modern and I think less in-your-face.

My one recommendation is, if possible, is to get the material from Lochcarron. I've seen the Grant tartan where the sett is woven smaller and to me, didn't look as good. I know that Lochcarron weaves it with the sett being large as seen in my kilt.

-Will