The blonde above with the dog is not me, just an advertisement for the boots. I find them warm, haven't had cold feet in them yet and I'm walking out in deep snow everyday and riding in them. My pants are tucked in as well... not sure, maybe google them and read up but I've been toasty in them... warmer than leather boots that's for sure.
Obviously they are rubber boots and not the warmest option as winter boots but I find they are the best option for winter when working with horses. We have deep bedding stalls so I want something waterproof and easy to clean off... most winter boots/leather boots you can't do that. I'm also lugging around pails of water and it's splashing so I find them ideal but if you are looking for a wide calf option the "Men's Balmoral's" are PERFECT. As for the other models of Hunter boots for women and the regular ones I don't think they are as warm nor do they go as wide. I'm only speaking about the Men's Balmoral line.
If you're not requiring a specific type of boot for shows, etc..., then I'd suggest getting some good lace up boots and leggings. I've used military boots starting out with my father's in 68 and later my own. Later I added the old WW I style military leggings. Works like a charm for riding and walking (if the need arises). No matter your leg size they can fit, because it laces up.
Have you tried ariat heritage contour field boots? They are cheap for the quality of the boot. My calf measures about 16.5 inches and I'm in a regular calf. These boots also have an elastic gusset which helps a lot. There is size charts for these boots on ariats site if you are interested. Be careful tho because I found that these boots stretch a lot after a month or 2 of wear. :)
There are tall boots out their that go up to 19. I've done a TON of searching. My calves are 21. X.x They don't even look that big, HELL everytime I go to a tack shop, they look at my calves and say of course we have ones that will fit you. And then they're surprised when they don't.
Oh I know....I have yet to find a tack store near me to have boots big enough to fit my calves (my calves actually look SUPER small but...haha no.) :(