Haha, they have their crazy moments, but overall aren't especially active. One of our neighbors has a shiba and they can only keep up for like 20 mins before giving up an trying to escape.
When my wife and I take them jogging, after about 2-3 miles they just find the nearest tree and collapse, refusing to move.
At least for the captoes, the 10UK are about the same width if not a tad narrower than an achilles in 45... But it's less forgiving because of the stitch where the patent meets the suede. If your pinky toe is smushed still in a 45 Cp you may want to go up.