I'm close in size to you and I know that after I spend a lot of time on a 52cm I'll be kicking myself for not going with the 54cm. Your body will relax with time spent on that bike and unless you're not very flexible, you'll want to be able to drop into a more 'aero' position simply because in time you'll find it more comfortable. Good luck in whichever size you decide on. The 52 might just be calling out to you for reasons we out here in the ether can't grasp.