Where did you get these figures from? By most reckoning 60 grams of carbs is the amount you would find in a bowl of porridge, if this ride takes 5 or 6 hours do you really want 6 bowls of porridge under your belt?
Note: I don't do sportives but as a Type 1 diabetic I do know about carbs. Although it does say "Sports Enthusiasts – recommended to take 2 tablets 10-15mins prior to participating in high endurance activity lasting for 30mins or longer, continue as required every 30mins." You can also get them in Raspberry which are nicer IMO.
What is a good carb intake for a long ride? I'm doing 120miles in May and have no idea about nutrition! I eat well but could do with some tips on (portable) snacks/supplements to keep me going. Those gluco tablets look good - at 90g of carb per 100g would a couple of those every hour be a good idea? Is that fact that 85g of that 90g of carb breaks down into sugar a bad thing?!
I can do 40 miles without any thing, providing I have fuelled the day before, yesterday I didn't do that but managed 40miles on a Mcvities flapjack (chocolate one) but in all honesty probably didn't need it. After that a couple of fig biscuits, jelly babies, cake, malt loaf, bananas all do the trick.