There was a guy posting a tool to make it much simpler and I think ED squashed it, even if they didn't they seem to not think multi monitor is very important, we pay for their stuff but they still expect paying customers to have to go through the UNFRIENDLY process of trying to figure out the math, through trial and error. I would completely agree with this if this were some armature community project! Best of luck to you, I'm too old to work for something I'm paying for already, so I no longer invest in the thing.