The Toto will gain you the 2". By code, you are normally required to have 21" (or 24") of clear space in front of a toilet. I am dealing with something similar as I had a wall mounted lav only 11" or so from the front of the toilet. It would hang over your knees if you sat on the toilet. Currently, I am relocating the lav, but will have to go close to the shower as it is a small bathroom and I am limited on space.