I would start with a 45 and get a nice cut to approxamtely .010". Lap the valve and look for a .010" seat to .010" lap job. See where you stand. If your happy with it come in behind with a 60 until the 45 and 60 meet. Once that end is finished then you can cut the 30 if the valve is sunk in the pocket until it meets up with the 45. You don't want to sink the valve unless necessary. If the valve is not suck you can kiss the edge with a sanding roll for smooth transition.