My 642 rides in the front left pocket of my jeans in an Uncle Mike's (inexpensive) pocket holster.
When it comes to grips and the "comfort" of shooting, let's remember that the MAJOR priority is not the ease of blasting away 50 or 100 rounds at the range, but rather the utility factor of getting five rounds off accurately when we need them badly.
What I've done is keep the factory grips on the gun, because they're adequate for me. In longish practice sessions I wear a pair of artfully padded shooting gloves, also from Uncle Mike's, and they are superb for taking the "sting" out of just about any handgun I've tried them with, including my .44 Magnum Mountain revolver (one of the original 1989 models). They leave one's fingertips free for proper trigger "feel", reloading, drawing etc., and are cushioned wherever a handgun is liable to bite one's hand. They're ambidextrous, too, which is important to us lefties! I highly recommend the gloves for their +/- $25.00 price.
I'm pleased to see recommendations for practice "from one yard out..." because this is the critical self-defense distance, in my opinion. Some of my practice is started by actually striking the target with a hand while starting the draw and then firing as soon as the muzzle bears, and commencing a move to the rear at the same time. Distance is our friend, but the action might start at very close range.
I live in the Nevada desert, and there are times when the pocket .38 is the most practical gun available. Given a choice and depending on the weather and hence the clothing I can wear, I usually carry a 9mm or .45 autoloader. The 642 is very comforting, all the same, and I feel well-armed with it and two reloads. It sees a lot of service in hot temperatures.