I'll add a bit more about the suspenders that I hope will be helpful. The problem is, they don't really follow the line of the boobs. The boobs will cause them to move a little less flatly. I used to have this issue all the time. I can't really think of any suspender items we have that you could reference but I would take a look at the buttons on some of the female blouses to guide you.

One hint I can think to give you, when it comes to clothing, lines are very seldom straight. Clothing has movement, and the lines will reflect this movement.