I have found in the past, when using rescues, that a ball position halfway between the inside of my front heel and center was the best for me. That being said, if I found that I was hitting ground then ball, I would move the ball slightly back in the stance, and if I was topping a few shots on the range I would move it a little forward in the stance. This helped me catch the ball at the low point of the swing. I always had a hard time with rescues going more left on my then I like so I currently play M6 fairway woods, 3 and 5, and the UDI 2 iron.
Let us know if this helps you.
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