Heat oven to 275 degrees F. Remove all wrapping from ham. Place in roasting pan, cut side down. Cover with foil and bake as directed.
Meanwhile, heat bourbon, water and contents of glaze packet in small saucepan to boiling. Reduce heat and simmer, stirring frequently, until spices are dissolved, 1 to 2 minutes.
To glaze ham, remove from oven. Increase oven temperature to 425 degrees F. While oven heats, brush or pour mixture over ham. Arrange clusters of grapes in pan around ham. Do not cover. Return to oven and bake about 10 minutes until ham is glazed a rich brown and grapes are hot.