1. I agree, GI Charts are all over the place. Start your own as everybody is different than the next person. Begin with eliminating white foods - white flour, white bread, white rice, potatoes, sugar. The purpose of eliminating these white foods will help get you started in adopting a healthier way of eating as they are high in digestible carbohydrates. High DC equals high glucose levels.
You mention bran flakes. Bran flakes are high in fiber and good for you. However, boxed cereal contains large amounts of added sugar put there by the mfg to add 'flavor'. Read the ingredient label on the box and find one that contains zero sugar or other strange ingredients. Like Dr Oz says, if you can't pronounce the ingredient or don't know what it is, put it back on the shelf and move on. Here's a sugar formula to remember; Every 7 grams of sugar listed equals 1.127 Tablespoons of refined white sugar in the US.
2. What is your goal? As a diabetic it benefits you [no sugar of course] by watching your carb and starch intake as these turn into sugar after digestion. Charts are published recommendations, not guidelines. You can start by eating low GI foods. Start a log for foods you eat, the amount, and eaten with what. Test your glucose before eating and 2-3 hours after to see how the foods you consumed affected your glucose. Once you have the low GI foods handled, then maybe try some moderate/medium but never in the high range. There are many GI charts listing foods consider low GI that to my body are considered high. Like I stated earlier, what is good for you may not be for the next person. Test, test, test until you know what is best for you.
"What is your goal?"
After bloodwork and diagnosis of 'glucose intolerant', I'm trying to get my numbers down from *Glucose,serum=130, C-Reactive Protein, High Sens=5.0 and Hemoglobin A1C=7.0 through diet and excersise.