I have had thoughts about this as well, and will provide what I would do if I were to go 24/7 for both purposes.
Wetting, as you do, will happen anywhere as it is non-intrusive and has no associated smell if you're hydrated well enough, and doesn't harm the skin if there is long exposure to the skin.
Messing, on the other hand, is a beast that is not to be publicly shown. If I need to mess, I will wait gladly until I am prepared to change into a new diaper because I've wet mine enough, especially if there is even a slim chance of being around anyone at all. If I am to be alone for the time period in question, I will go only 30 minutes at the most before a change but I still won't waste a diaper that hasn't had at least half of it's potential capacity soaked up. Sure, maybe the odd time I'll dare myself into messing in public, but then I'd just avoid people. That's the thing with messing, avoid people, messes smell bad and you don't want others to smell it.