When you downtune your guitar it becomes easier to play as Tony Iommi did back in the day when he messed up his hand. I was wondering if there was a ratio or scale on how much easier it becomes to play based on the tuning. Say you have a set of 10s and are in E Standard. If you tune 1/2 step down would it feel like you are playing a set of 9s or would you need to tune a whole step or more to get that feel (how easily you can bend, legato, etc even though the string is still the same size). Say you tune down 2 full steps, what gauge strings would you need so that it feels the same as playing a set of 10s in standard?