What is the best method to reduce a vertically long chin and give it a v-line shape?

I am a woman with a long square chin, and I would like to reduce my chin vertically (not horizontally). However I also have a lot of soft tissue on my chin, and when I smile the soft tissue chin pad pulls down and looks droopy. Would a T-Osteotomy be a good method to make my chin shorter and more v-line? Or would this method cause my chin pad to sag? Would a submental chin reduction be a better option? I would like to shorten my chin by at least 5mm - 7mm.