Leave the wood grips on the speed six. Plastic or rubber grips don't handle well on a 357 revolver. Get the over sized wood grips from ruger or ebay. Then have a gunsmith cut them to fit your hand if needed. I bought the rosewood over sized grips for my blackhawk and I am very happy with them right out of the box. I got mine from numrich for a better price than ruger offered. You might find target grips on ebay for a fair price.