Mmmmm, I would stay away from spring weight fabric. It's actually harder for a beginner to make a kilt out of lightweight tartan than heavier weight tartan. You'll also find that the pleats don't hold a crease well and that the tartan wrinkles really easily. And it flaps around and doesn't look "kilt-like". Not much swing, either. And 8 oz fabric doesn't have a kilting selvedge, so you'll be obligated to have a hem.

Lots of the guys who live down south are happy with their heavier kilts and don't find them hotter. I have to agree - my band kilt is 16 oz, and we march in parades and compete all summer, and it's the kilt socks that are the real killer. The only hot part of the kilt is right underneath the belt, but that would be true if the kilt were lightweight as well. Air circulates nicely under a kilt to keep you cool.

And truly, if you're talking about buying tartan, spring weight tartan isn't _that_ much less expensive than kilt weight (13 or 16 oz) tartan. If you want to save a little money, buy heavier tartan, but get 7 yards (3.5 yards double width), and have fewer slightly larger pleats. You'll be happier!