Hey Rob, I do most of my running in the Kinvara with socks (11.5) and I ordered the Kiawe in the same size. The are much more snug, and I only wear them sockless w/ the elastic laces.
I don’t find them to be much shorter, but they are definitely lower volume in the mid-foot than the Kinvara. I recently discovered that I have a low-volume foot when I got some S-works Trivent shoes and had to get rid of them because the BOA bottomed out before the shoes were snug.
I got a little bit of cramping in my first run in the Kiawe, but they have stretched a bit. It definitely does run more snug than the Kinvara, but I still think they are “true to size” in terms of length. If you have a higher volume foot, they may not work for you.