Hey ladies! I need your advice. I'm definitely going to buy Spanx to wear under my dress to make me look smaller. I'm torn between two types. Any recommendations? This is my dress:

The two types of Spanx I am deciding between are
this one and
this one. I like how they come up high and have the thighs covered. I just want whichever one will hold me in the best! Suggestions? Thanks for your help!