I went back and looked at the Balmoral photo again and I still think that the hose are a very poor match for the kilt.

The hose are 50/50 red and offwhite, while the tartan is predominately grey. (Note that the hose match the Dress Stewart drone ribbon much better than the kilt.)

If designing tartan hose for that tartan I would make the large 50/50 areas two tones of grey (pale grey and mid-grey) as in the tartan, with fine lines of red and black/charcoal grey as in the tartan.

BTW in The Highlanders of Scotland there are a few men wearing kilts of Balmoral tartan, and they are all wearing plain grey hose.