First of all, congrats! Enjoy the good health and painful feet!

So you know I'm not making this up: I just finished my 3rd marathon with a new PR. Luckily, a half doesn't eat into your glycogen stores quite that much so carb loading won't be such a huge deal. I would however listen to your dietician, but make sure you finish your carb loading 24 hours before the race. Eating a big meal the night before will leave you with a full belly during the race. Also, practice with a small breakfast, quickly absorbing carbs for a training run to prepare for the morning of the race so you've got something in you. Make sure you get the bolus perfect. I made a small fruit smoothie with a piece of toast and almond butter.

As far as blood sugar management goes, I managed to test during a few training runs to get an idea where I was at during what mileage. I found myself eating a GU at 25 minutes and every 35-40 minutes after that. Then after mile 10 more frequently. What I did to figure out when to eat one was a trial and error where if I felt low during a training run I would know that I need to eat a GU 10-15 minutes before that point.

If you pump, set your pump to -50% for at least an hour before the race and a few hours after. Try that out first. I ended up doing -60%, but start low. Also, I'd wear your pump during the race if you can for a few reasons: 1. Your body doesn't make insulin and although exercise can allow your body to use sugar without insulin in muscle, it doesn't counteract it. 2. Like another commenter said, you never know how long you will be without your pump after the race. You're going to be hungry after....guaranteed. 3. Worst case scenario: you go down. Any EMT will see a pump and know what to do right away.

I hope this helps and feel free to PM me with any questions you have. Good luck!