If you use less insulin, you should gain less or stop gaining weight. Weight loss is sometimes a complicated thing.
A little over a year ago, I decided that I wanted to gain much better control over my blood glucose levels. I wanted to drop my BG average and A1c while also reducing the BG roller coaster. Weight loss was not my goal.
I adopted a "lower carb" diet, about 50-70 grams/day. I lost 23 pounds, about 15% of my body weight in 90 days. Surprisingly to me, I used very little willpower to do it. My average BG and A1c did drop and my glucose variability as measured by standard deviation dropped as well. My total daily dose of insulin dropped from 60-80 units per day down to 30-35 units. I weigh 160 pounds now.
Prior to that I had gained about 20 pounds over a 15 year period. My total daily dose of insulin went up from about 40 to about 60-80. So for me, more insulin meant more weight. From what I've read, insulin is known for putting on fat.
Looking back, with that 20+ pound weight gain, I became resistant to insulin. Insulin would not act in predictable ways. Sometimes a correction, for instance, would have no effect at all. I've read more recently that insulin resistance is not unusual with T1Ds, a fact that I was unaware of when it happened to me.
Lower carb was the magic bullet for me. One thing that I tried prior to lower carb was to inject a set amount, a lower amount, of insulin and try to only eat a smaller portion of food that would hopefully counteract the insulin. I couldn't make that work with the usual carb portions.
Whatever you do, I recommend that you keep a written record. It will help you make adjustments, mark your progress, and help you see some longer term trends.
Good luck -- losing a few pounds is a great goal!