Ballast Drainage Questions

When using reversible pumps would you rather drain from the same intake (bottom of the boat in this case) or add check valves and a T before the pump so when you reverse the pump it it will pull it back to the check valve then T off to the vent line and drain from the vent where you can see it.

Draining from the bottom of the boat is a much easier set up but you can see when the bags are empty with the vent drain set up. Let me know your opinions on the route you would take an why.

Thanks