Put maltodextrin (glucose) powder in a long effervescent tablet tube
Per hour: 0.5L isotonic energy drink (30g carbs), 1 gel (25g carbs) and 1 portion of solid food (small energy bar or homemade rice cake) (10-20g carbs) - for a total of ~70g carbs. This pretty much replenishes carbs burned for an endurance-pace ride.