I would like to know if anyone has done any test flights to determine the roll rate at various airspeeds during thrust reverser deployment at different power settings.
It's hard to get pilots to fly a test like this.
They much prefer some lesser tests and lots of extrapolation.
at any rate airspeed is your friend as it destroys the reverser efflux and sensitizes the wing control surfaces to work as planned.
Of course nothing is 100% so the FAA now requires a few more hoops to jump through before saying that it's good enough.