I would only offer one suggestion when it comes to rubber grips. They tend to trap moisture against the frame. Be sure to remove them often and use a silicone cloth to prevent rust damage to your gun.
I put a pair on my 640-2. They fit well, absorb recoil, cover the backstrap and take little away from concealment. I appreciate them most h n shooting magnums through the 640.
Don't try the Pachymayer Diamond grips on a N Frame 44 Magnum. Purchased brand new and tried to the result of knuckles banging off the uncovered SS Trigger guard ... OUCH !.