Elk,
my knee socks are Smartwool Ski socks. STP has some on sale at the moment:
http://www.sierratradingpost.com/Pro...f=AffinitySale
Not sure how heavy those are compared to mine. I paid about $17 for my SW ski knee socks, medium cushion. I think mine were men's small....

XXL might be too big for your Spinnakers- they aren't that tight and stretchy- more relaxed. You'll just have to see when they arrive.

Sandra needs an XL switchback- Ibex only has that size in periwinkle color- with no photo of the color. I'm not sure what periwinkle looks like. I'm not seeing many XL switchback full zips left on the net at this point.