Anyone with t1d that does Iron man or similar endurance races

My first long endurance race took 7 hours, a 35km trail race with 3 mountains and about 1100m above sea level. I did no correction to my basal, and In had to eat every 20 minutes to keep my bloodsugar around 3,7-4,2. I didn’t take any bulus for the entire race.

This year I decided to take on an Iron man 70:3, but in this race I decided to almost cut my bolus in half. Unfortunately, this completely backfired. I was in 15-20 during the entire 90 km cycle leg. When I reached T2 I had so much cramps due to my body barely reciving any nutrition. On that as well, I forgot to take basal so had to quit after 3,5 km running which I was really disappointed at.

I’m gonna signup once again next year, but i’ curious if there are any people that does these kind of races/training here that has any good stories or tips.