I just did a lot of research on toilets and chose a 12 inch rough in model for a new house. My builder then informed us that 2 of the 4 new toilets are going to have to be 10" which eliminates my first choice. The house specs call for 12". Should we ask him to change the floor joists to comply with the plans? Should we ask him to pay the difference between the Drake II that I wanted and the Vespin, which has the same tank that Drew me to the Drake II? Will it be difficult to find 10" replacement toilets in the future? (I renovated a bath once with a 14" rough and it was a huge hassle to find the right toilet). Last question, can a Drake II tank go on an Eco drake bowl or other 10" bowl?