The elastic is not required in and of itself; however, it can help with the fitting. Looking at all of your submission pics, I think you would benefit from having the chest attached to the abdomen with elastic. I recommend doing so in three points. I have TK-based suits with elastic and without, and the ones where I employ the elastic between the chest and ab definitely fit better and troop easier. In other words, I think it looks like you need it in all of your poses.