If you are looking for rain pants, I wonder why you are looking at the 90% pant.
Dew point or Cloudburst are more what you are looking for.
My favorite pants from Sitka are the Mountain pant, and the Timberline pant.
Its a knee pad thing.
I have other pants from Sitka, without the kneepad, but love the knee pad pants.
Your post kind of got high jacked by the KUIU band.
I like KUIU.
My favorite pant from them is actually the Tiburon.
Best warm weather pant I have ever put on.
The Chugach and Yukon pants are both good options for waterproof rain pants.
I definitely would not want to rely on my Guide pants or Tiburons for rain gear though.
Things I LOVE about Sitka pants are the tack strip in the waist band, knee pads, and durability.
Things I love about KUIU pants are the price, the un hemmed legs, and the weight.
But, I assume that since you asked specifically about Sitka, you have a Camo preference as well.
I prefer a range of camo options, but if I had to choose one, it would be the Optifade open country.
You might find that the 90% pant works for you, but you might have to carry some light weight rain gear for the heavy down pours.
Or, Save up a bit longer and go full waterproof.
I don't care what brand you like, getting wet SUCKS. Its Even worse on a hunt when you are on a timeline. I would not want to get stuck out in the rain without anything but 100% waterproof gear.
But, thats just my opinion.
Knee pads man! Knee pads.
If Sitka made the Timberline pant fully waterproof, (currently only the knees and butt are waterproof material) I would sell everything but the Tiburons and stock up on Timberlines.