After three more iterations today of accelerating then stopping GV12's VFD-driven motor following 0 - 300 rpm, stop, wait (hours) 0 - 300 rpm, stop, wait etc. pattern, the MEDM screen position indication finally transitioned from RED (CLOSED) to YELLOW (not CLOSED, not OPEN). 

I had noted initially that, when fully closed, the ball screw is recessed below the pulley nut(?) about 10 inches.  Today, when the CLOSED limit switch transitioned states, I noted that the ball screw was flush with the pulley nut.  Hmmmm...if this is by design, then this could be helpful in the future when assessing the degree of closure for these valves.  On related note, when fully open, the ball screw measured 37 7/16" above the pulley nut.  The hand marked measurement (written in ink pen in the vicinity) for this left by whoever inititally commissioned this valve back in 1997/8 was 37 9/16".  I wonder if this discrepancy is due to casual measuring, or, would I have achieved 37 9/16" today had the valve been driven to the OPEN limit switch at full speed?