Momo, they are quite comfortable, right out of the box. I decided to pass along an old pair of burgundy boots because the heels (3.5" or more) have become uncomfortable for me. So on a whim, I thought I'd order these while I ordered another pair of boots to try. I thought I would be lucky if either one was a hit, but they both ended up being winners. I didn't walk a ton yesterday in them (this was the first outing), but I was on my feet standing a lot, which is even harder on comfort IMHO.
I have long calves, and these end up nowhere near knee height on me, so I think they'd work well for someone shorter. The calf is not too narrow (my calves measure 14.75-15" for reference), but I noticed that these are available is wider calf widths too. The laceup detail at the back gives a little extra flexibility on fit.
As I wore them throughout the day, they scrunched at the heel a bit, but I expect that of pretty much any tall boots. They are not stiff, so that didn't result in rubbing on my ankles, which has been a problem for other boots.
So TL:DR -- I recommend them! Let me know if you try them and how it goes.