The 90% are great in later seasons but, in my opinion, too hot for early season. True, I'm bowhunting in September, so if you're a rifle hunter it might not be as big of a deal.
Lately I've worn the Ascent pants in the early season and/or the Mountain Pants if I'm hunting up high where it might be a little cooler. Last year, for instance, I hunted high and it was crappy, rainy weather in September and the Mountain Pants were perfect. In truth, the 90% would've worked for a couple of mornings because it was downright chilly.
In November late seasons the 90% pants are awesome.
The suggestions of where to purchase are good. Also,
http://www.high-mountain-outfitters.com have frequent sales on Sitka.