I am remodeling a bathroom. I left the toilet drain line in place. I'm getting ready to lay durock and tile, so I was measuring the distance between the wall and center drain line to make sure I could use the Kohler Persuade toilet I had planned on using. Unfortunately, I'm just now realizing that I only have 11". The Kohler Persuade calls for 12", with only 1/2" between the tank and wall. I have no experience with offset flanges, but is this something relatively simple to pop in place of the existing the flange? I know other 12" toilets are a little more forgiving, so I can just go with a different toilet if the offset flange is an issue.