First, Stan, glad to hear that your PG is slated for replacement. Wise decision....
Can't help you on that rubber grip. You could do the old NYC cop routine and wrap rubber bands around the grip until you've achieved non skid surfaces. Nice part about that is it's easy to undo.
As for the Terminator speed rack, back when I was intructing, we had some down time on the range when shooting a shotgun one handed came up. I believe this was around the time of the FBI Miami shootout,where one agent did some work with an 870 after taking a 5.56 mm round in his left arm.
So us instructors put up some targets, grabbed some training ammo,and commenced to experiment. We tried some different techniques. The most effective one was to shoulder the weapon and fire. To cycle, one shoved the weapon forward, then pulled back sharply to cycle. This was fatiguing, but it worked. Second best was to trap the butt UNDER the arm, fire, keep the stock clamped under the arm and reach forward and pump it with the strong hand. There was a tendency to drop the weapon this way.
As for damaging the weapon by cycling briskly,don't worry about it. Most pumps function when cycled that way. Some will hangup when stroked gently, or fail to lock up. The old S&W 3000s were prone to this,especially wheh dirty.