Thanks for your response . . . the whole idea of course is to avoid strobing altogether. The 150 degree shutter at 25 fps is exactly 1/60 which theoretically will eliminate 60hz flicker.
On set the 150 degree shutter did work - except that we were filming in a theatre with the projector set to 24fps! In the end the fluctuation of the projector was acceptable as our key lights were not flickering when we set to 1/60th shutter . . .