I have a pr of Whites cowboy pacs just rebottomed by Hoffman with cowboy bottoms. Easy to fit in a stirrup. I wear a size 9.5 in a mountain boot, are size 10 fit well with room to move my toes. Thought about the regular bottom, went back and forth but got cowboy, dont regret. Have also used arctic shield boot covers over uninsulated lathrop mountain hunters for long periods of inactivity that kept my feet warm. This year used 400 gm insulated boots on a horseback hunt that had temps in the morning in the 20s with 2-3 hr rides, feet got cool a few times but not cold. Used them rather than the pacs as we were hunting at 11k elevation and had fair amount of walking in sketchy terrain. If it were colder for longer periods either 1000gm mountain boots or pacs