I have those boots in the BOA version. Like you, I wear a size 11 1/2 athletic sneaker. I have both the size 12 and size 13. I have only worn the size 12, and only twice.
They felt fine in my Dryft waders. I thought that they were too big while wet wading over my NRS neoprene wading socks. I like to wet wade when possible.
Almost all of my fishing is done on the Tobyhanna Creek in the western Poconos, which actually gets too warm during the summer for trout fishing.
I haven't yet, and don't want to use the studs that I also purchased. I want to wet wade and walk into the local bar without damaging the bar floors.
So far, I like the boots and the BOA lacing, but have only worn the boots twice.
I have not worn the size 13 yet. I have a NRS dry suit that I also haven't worn. I have that for winter fly fishing, which will be new to me this year so I don't know which size boot will work best with the dry suit.
I have several wet suits and have first hand experience with hypothermia from canoe trips. I take hypothermia very seriously. The dry suit my seem like overkill to many, but not me. I have experienced hypothermia, and it permanently scared me into spending money to prevent that from ever happening again.
So far, I like the Orvis Pro Wading Boots better than my Korkers. They are much easier to walk in from the stream to the local bar, but I have only worn them twice. I am thinking that I may need to size down to 11 for wet wading, but I haven't worn my NRS dry suit yet to know if I need the size 13.
I hope that little bit of information helps you.