To me a scotch ale is not a scotch ale unless it is done with a British base malt and British hops. The recipe of a true scotch ale is simple. British pale malt, take the first gallon of runnings and boil it down to half a gallon to caramelize it, get the rest of your runnings and boil. That gives a caramel flavor and darkens it. Or you can make something that tastes really close by adding some caramel malt to British pale for flavor and some black patent for color.