We've gotten pretty good at draining & refilling the coolant system ... because we've had to fix so many leaks.

One of the royal pains was the radiator outlet. It was trapped inside the radiator frame. In order to open the drain we had to remove the radiator mounting brackets at the top, then shift the radiator up and forward.
So, we needed a solution. More JB-Weld and a few fittings along with a ball valve. We drilled a hole through the handle so we could safety-wire it in the closed position.