Remove ham from fridge; let come to room temperature (1–2 hours). Score ham in diamond pattern, 2-inch cuts, insert garlic if desired.
Preheat oven to 425 degrees F, bottom oven rack, and prepare large roasting pan with elevated rack.
In small bowl, mix salt, brown sugar, black pepper, garlic, thyme, rosemary. Rub over ham and into scores.
Place ham on rack over orange slices, pour cups of water and wine in bottom of pan.
Roast at high heat 425°F for 30 minutes. Reduce oven to 300°F; cook until internal temperature 140–150°F. Tent with aluminum foil if browning too fast.
Optional: Brush glaze at 130°F, return to oven until final golden perfection.
Let ham rest 30–45 minutes. Slice with sharp knife, serve with pan drippings, mustard sauce, or side dishes