head flow experts need opinions on intake flow

Don’t the valves rotate while running? Serious question.
No.

Only if there's a rotators. You may see some rotation on stock low spring pressure stuff...BUT Otherwise, no. With a heavy performance oriented spring..the pressure is enough to not allow spin. when the valve doesn't spin, the guides clearance allows movement from forward thrust of the rocker actuation and a seat/valve wear pattern that is no longer round is hammered/formed.
The exhaust valves are really good example here with the Performance Engine ...spin the valve 90° then put it back on its seat and shine a light through it and you'll see light on each side. More heat...more distortion.
This is why I made sure to recommend marking the valve so that he may put his heads back together and not have any problems