At my last riding lesson, I tried the toe warmers and they fit inside my boots just fine. Maybe I don't have the same type as you. This type is sticky on one side and you stick that part to your socks. My feet were nice and toasty!
Winter paddoct boots(with fuzzy socks), suede half chaps, long johns and jeans, I have found the best for very cold day, add wind pants over top, can ride in if you have a trustable horse and only trotting around!