You've completely floored me there Ian, why is bending your wrist not a good thing?
If you are brushing a curved surface, such as a ship's hull, don't you have to bend your wrists to ensure the nozzle remains perpendicular? I always believed that bending your wrist was key to ensuring consistent coverage and it's something I practise to try to get right.
If you don't bend your wrist surely you then have to move your whole body, or at least your entire arm to keep the brush at the right distance and angle, which has to be considerably more of a challenge.
I think it would be very interesting to see what other experienced modellers think of thier own techniques and how they compare.