West and East Scotland
I did some number crunching and found that if you divide the country into a socialist independent west and a UK member state east part (ala North and South Korea), it would work out like this: Socialist West Scotland gets all the light blue and light pink bits on the map in my last post (except Dundee is traded for East Renfrewshire for geographical reasons... also put Argyll and Bute into the West despite their lower yes vote).
With 14 council areas, the West would have 2.5 million people (47% of population) and 16.2K sq miles of land (53%). Should be more than a fair solution.