I think you really need to have some kind of strategy for this. Your reasons for wanting to gain weight, the kind of weight you want to gain and your insulin sensitivity are important considerations. Are you underweight because you lost muscle when you became T1? If this is the case, you should be be doing what it takes to build new muscle. In addition to looking and feeling better than carrying extra fat, increased lean muscle mass improves insulin sensitivity. It gives you more control over your blood glucose. You build muscle by by doing resistance exercise and using protein supplements.
Join a gym and get a trainer to help you devise a an exercise program. Exercise also stimulates appetite, which it sounds like you need. It sounds like you are getting enough carbs, and increasing them further will make controlling your blood sugar more difficult. Getting those extra calories from eggs, cheese, nuts etc would serve your cause better.
