I would say Argyle jacket and five button waistcoat, to go with your Ruche tie. A dress sporran would look better than a plain leather one but the chioce is up to you same with a Sgian you dont need one but if you want one...

Hose colour will depend on your tartan as well but gray with red flashes might work or red to compliment your tie with dark coloures flashes

Just my tuppence

Jordan