I have always had a problem eating the right number of carbs before-during-after intense exercise so that I don't enter an exercise period with a full stomach, or go low during or immediately after an hour long exercise period. Evidently my liver doen't churn out the glucose exactly when I need it. lol. That's part of the nature of this disease -- a body that doesn't do what normal bodies do.
After a couple months of testing, eating different foods, and tracking how I feel, this is what I've come up with for now. Eat normally before, avoiding any carbs that are going to spike and then drop the blood sugar. DUH! Have the last snack size meal about 1/2 hour before the session begins. Eat 1/3 of a "Cliff Builder's Protein Bar" (total bar = 270 calories, 20 grams protein, 30 grams carbs, 7 grams fat) immediately before beginning the personal training or water hydro session. That's all I need for the water class, but for the land weights and core strength class I need to eat another part of the bar every 15 minutes.
I've tried this for the past month, and I have approximately the same meter reading before and immediately after the session -- about 115. Hooray.No more quitting in the middle of a session because I am light headed and can't perform the moves. I have a small snack after leaving the locker room on the way home. Like one hard boiled egg, 1/2 apple or some berries. Resume normal eating for the rest of the day.
This may sound obsessive, but I was missing exercise sessions due to being light headed and out of eneregy, or too high and dizzy to continue. Neither was good. This way I get the maximum exercise and really enjoy it. For any self directed exercise like walking, I can just put the food in my pocket.
Please notice the topic said "MICROmanaging", so I am not recommending this except to obsessive posters like me.

If at first you don't succeed, try, try again!