the expensive sports drinks use Maltodextrin, not sugar or fructose, as your stomach can absorb it faster than other carb sources. It does not have any taste so add what you want for taste, plus any salt or whatever.
It is pure carbohydrate, so it has 4 Cal per gram, and should be mixed such that you are taking in about 250 Cal/hour....so you need to consider the termperature and your sweating rate....for me I drink 26 oz of liquid per hour in 80 F and riding a very hard pace, so I add about 70 grams of Maltodextrin per bottle.