I used to worry when I was first diagnosed ...

I'm Type II, I use water for rides under 30 miles, and Gatorade/PowerAid for long rides. On a short ride, if my sugar drops and I start to get "that feeling", I use a gel pack or Power Bar about halfway through the ride. I have had no A1C (avg. 6.8-7.1) issues when I get my blood work done every 3 months.

When you are on the bike, riding, your body is burning sugars as fuel. They are not building up and shooting your sugar levels up. Just fuel as needed, and slack off 30 or so min. before the end of the ride, to be sure you burn up the sugars you last ingested before you get off the bike.

I'm not a doctor, just speaking from my own experience over many years of being a diabetic cyclist.