I put one of those "grip adapters" on my OM-4, and it helps. I have since put winder-2's on all my OM's, no more problems with them feeling small. Naturally, if you hold one properly you don't have that, as you are supposed to rest the body in the palm of the left hand and gripping the lens, whilst the right is for shutter release and film advance, not a death grip..
Yes, of course, but not having anything to hold onto doesn't help for carrying the camera in the many minutes or hours you're not pushing the button. :-)