Don't worry about matching too much. I think the Lovat blue hose look far better than the ecru coloured hose you are wearing in your first photo. For your specific tartan, I think the following colours would work well:

Fawn (oatmeal/stone - a bit darker than ecru and off-white)
Claret
Tartan red
Brick red
Dark Natural
Brown
Mustard
Loden
Bracken
Lovat Green
Mid-grey
Charcoal grey
St. Andrew's blue
Blue mix
Lovat blue

And of course the colours above could be used to create pleasing colour combinations with kilt hose or country socks that have a coquet, or 'diced' cuff (turnover).

Best of luck,