Don't be impatient. The slower the weight comes off the longer it will stay off. The simplest way to diet is to just reduce the overall size of each meal. One slice instead of two and one less potato etc, rather than cut out carbs. Cutting carbs is hard with type one, and unnecessary to diet.
Eat less, do more, and the weight will come off. If it only comes off at a pound (1/2 kilo) a week, then that's fine, it's much more likely to stay off because you will be eating a diet that is easy to stay on forever. Never try and 'diet' deliberately for the time it takes to lose the weight and then stop. You have to learn a different level of eating that simply does not take in more calories than you use up.
And if you take more exercise too, then you burn up more calories. So yes, dieting is not so easy when insulin is in the equation, but as you obviously know how to adjust your dose to what you eat, it shouldn't be a problem for you. Just don't try and diet all at once. So what if it takes a year? It's if the weight stays off that matters, and that you can keep eating the amount that keeps your weight stable without feeling you are eating less than you want. And you will only do that by slow, gentle dieting, not by drastic 'I've got to lose loads in a month' type of dieting.