I recently decided to give open carry a try, mostly because I really like my full size P320, and haven't gotten around to picking up a smaller kit yet. While certainly not impossible to conceal, it's definitely not designed as a concealment weapon. I'll probably go back to concealing after I pick up a carry or compact grip for it.
I could carry a smaller pistol, but this one's my current preference. I can open carry legally, so I do. It's also just easier as I don't have to worry about putting on different clothes to conceal anything when I leave my property.
If I have to make a trek to St. Louis, or anywhere that I can drive for work, I'll take something a bit smaller and more concealable, however. It just depends on what the day calls for.
Most days, I'm not going to stray too far.
Sounds like MO is similar to NV, where signs are to be posted when guns aren't welcome in an establishment, but don't carry the force of law, unless you choose to not comply when someone asks you to leave.
I tend to avoid those kinds of places out of convenience. But when you can't avoid it, you can't avoid it. I have a vault in the truck to provide that little extra bit of security when I'm not carrying. Then I just look silly with an empty holster.
I definitely don't carry open or concealed if the place is prohibited by law, either federal or state.