Of course diced hose, either red/white or red/black, are classic and would look great with the Black Watch tartan. But if you are after a pair of Argyle hose (knit to match the tartan) then just order a pair specifically to match the Black Watch. There would not be a lot of color contrast, but as Argyle hose are typically knit to match the tartan, it is what it is.

We have stock of the diced hose in the shop now for immediate shipping:
http://giftshop.scottishtartans.org/hose_argyle.htm

Here's the custom knit Argyles:
http://giftshop.scottishtartans.org/hose_custom.htm