Pretty much what Badger said. If you want it to look good buy the bars and risers you want then take the measurement for the best fit. Usually when you order cables you order them + however many inches above stock. For example, when I put my apes on I put 18" apes and ordered my cables +12 above stock. Another suggestion is to run the electrical through your bars. Makes for a cleaner look. If you need any help just ask. Maybe we can have a tech day like we use to. Here's a pic of my apes.
X with Apes.jpg