Hi Rainbow,
It really is frustrating trying to get the fit right...even more so when having to deal with online returns. Have you considered shopping at a store like Torrid or Lane Bryant? They specialize in plus sizes and are very friendly to the CD and TG community. There are also stores like Kohl?s that carry plus sizes and have non gendered dressing rooms. Going into a shop like that for the first time, especially in man mode, is terrifying. But after you do it for the first time, there is no stopping you in the future. It truly is an exhilarating and empowering experience.