Thoroughly rub pork shoulder with mixture of salt, seasoned salt, garlic powder, black pepper and M.S.G. Place fat-side up on rack in shallow pan. Roast at 325 f. for 40 minutes. per pound to 185 F. on meat thermometer. Remove skin and score fat in diamond pattern. Pour mixture of honey, ginger and horseradish over scored fat. Return to oven. Roast for 20 minutes longer until well-glazed.