Whether you hold the grip and rack the slide, or hold the slide and move the frame, you still have to have a tight enough grip on both that neither one slips in your hand. Like many other guys who are getting arthritic in their hands or have had issues like carpal tunnel, where you lose grip strength, being able to hold the slide tightly enough to either pull it from behind or grip it over the top and slide it backwards is getting more difficult. This seems to be even more difficult on the pistols chambered in .40S&W and 10mm for me, as the recoil spring is stronger. I have no issues (yet) with .38 Super or .45 Auto (I don't shoot 9mm much).
I've started gripping the top of the slide at the serrations in back, thumb on the left side, and right index and middle finger on the right side serrations with my index finger "jammed" against the rear sight, which helps move the slide with a less tight squeeze on it. Since I carry C1, I only have to do it once while carrying, and it's a lot easier at the range when doing it multiple times. I hardly ever racked the slide by pulling from the rear anyway.
When racking it to remove the live round after removing the magazine, it throws the chambered round into my hand.
