Probably try the 8 hour megamax pullups for capacity? And then work backwards till you know what capacity works best for your needs.
PUL plastic pants are reasonably discreet if you’re worried about leaks which is a high possibility as you'll be sitting more often.
Putting a loose fitting pant (diaper pants) over the top to give more discretion and silencing the PUL pants.
Over all of that a snap crotch onesie works well to hold everything in place.
Trying different things is the only way you’ll know what works for you.
You may have to plan for the worst case scenarios where you did have a leak. Can you get to the bathroom without being caught? Scheduled changes/breaks to be sure there’s not any issues throughout the day maybe?
The PUL pants I have are custom off etsy and have gussets which has worked really impressively compared to other ones without gussets.
Good luck!