Shooting from a good rest is a good way to see how accurate your revolver is, but it is not a good way to see where the gun is going to hit when shot off hand. Whether your rest is hard or soft, and how you hold the gun does make a difference. When I was a cop, and a Instructor, I used to see a lot of guys shooting from a barricade position, resting the gun against the wood post. It usually threw their shots wide. Guys who rested their forearms against the barricade always did a lot better, so yes, recoil does effect shot placement before the bullet leaves the barrel.
I always shoot high left with my single actions, no matter how much I concentrate on the fundamentals. Don't have that problem with double action or semi-auto handguns. Just the way I grip them, I suppose, since accuracy is not an issue. I long ago came to terms with all my S/A sights being adjusted low and to the right.
I would try different loads to see what regulates closest to your sights, fired off hand, then try different grip styles, such as your little finger under the grip, left thumb resting on the recoil shield, etc. Once you settle on a grip you like, and a load, then fine tune your sights from there.
When I shoot a handgun from the bench, I try to rest my arms on sand bags, with the gun out in front of me, minimizing the effect of the gun bouncing off the rest. I shoot from the rest for accuracy, and not necessarily point of impact, as it will vary from off hand.