A water brake or even an inertia dyno is NOT for most driveablity issues. That’s not what it’s for. So why abuse a tool for something it’s not designed for?
It’s amazing the number of guys who think what happens at 2000 RPM is critical, or really even important. What matters down that low is mostly a tune up issue.
How well the engine transitions from the idle circuit to the transfer slots and then on to the mains is far more critical that torque. It’s mind boggling how guys get this wrong.