What size? Colour?

I am 5'2, 110lbs... thin to normal build for my height, small chested, and usually wear XS or S. I own the North Face Women's Hooded Elysium Jacket in size S and Nuptse Vest in size S -- both are too large. I have a Summit Series shell (don't remember the product name) in XS and that fits perfectly. I am planning to purchase the Arctic Parka in XS, however am worried from the reviews that it will run small. Should purchase a size S instead or stick to XS? Any advice?

Also, any opinions on either Bittersweet Brown or Ink Blue colour? I'd prefer the Ink Blue only if its more charcoal grey in colour as opposed to a faded washed out blue colour, which I want to avoid. Or should I go with the Bittersweet Brown? How dark is it? It's so hard to tell from web photos!

Thanks!

Tech Specs:

Material:

[Shell] 70D x 157D HyVent nylon twill 

Insulation:

550-Fill down 

Hood:

Yes 

Pockets:

2 Hand, 2 chest, 1 internal media 

Waterproof:

Yes 

Core Venting:

No 

Weight:

56oz (1600g) 

Recommended Use:

Casual winter wear 

Manufacturer Warranty:

Lifetime 

Country of Origin:

China