What do you recommend for calorie intake per hour during an Ironman?
That really depends. For most people its around 200-500 calories. Some like to get the calories all from liquid, some like to get it from food and liquid. If you haven’t yet read it, pick up a copy of Going Long by Gordo. Its got an excellent section on race nutrition, how much to eat, what to eat, how to time the intake of the calories, etc.