Generally for exercise 60 minutes or more you want to fuel with 30 to 60 grams of Carbohydrate per hour. How much and the type of fuel is highly individual. For example, someone who sweats heavily may prefer a gel with higher sodium content or you may prefer the flavor and texture of one gel over the other. There are some who find that real food settles better with their stomach. (Check out the Homemade Fig Bar recipe).
During your training and if you have any practice races leading up to your "A" race is the time to experiment with what does and what doesn't work with your system. Again, I've created a chart of some general guidelines to use as a launching pad for creating your perfect strategy. For during-run hydration please reference Creating your Hydration Profile.