Porridge, I'm in Chicago for law school, but not from here, really. I was in O'Hare a few hours after you!
So the BF won't let me see it until the proposal (I've never seen the stone in person so there's a LOT of surprise left to be had) but he agreed that it should be knife-edged and we're also going to ask BGD to slightly adjust one of the prongs (the bottom right one in the head-on shot).
So, back to LIW for me while I wait for him to pop the question!
Your ring is stunning! I can't wait to see the real life hand shots. You can't go wrong with either setting. It will be just as gorgeous if you decide to go with the knife edge.