The best recoil aid I've ever used is the shooters shirt made by Evoshield. It has a pliable soft insert pad which is vacuum packed when you first get the shirt. You have to take the pad out of it's packaging then put it in the shirt and mount your gun several times in your normal shooting position. The pad forms to your gun and body & then hardens. This spreads the recoil over a large area and you have no felt recoil when using it.
I've used these shirts on several Argentina dove hunts where I've shot over 10,000 rounds and never had any shoulder hurt or discomfort of any sort. I have also used most of the other strap-on type pads down there and would not recommend them based on my experiences with them.
