Sorry. Tough love time...
You have some 20 posts on here asking a bunch of questions that would be answered if you took a tape measure, some tape and cardboard, and the spec sheets of the toilets in question and made a crude 3-dimensional mockup of just the last 6 inches of the thing, then placed it on the floor at the point where the round bowl ends and then again where the pointier elongated ends. You can tell right away what the difference will be.
Professionals do this all the time because until you can see it, you're going to agonize about dimensions that are meaningless in real-world applications.
You don't want to do a mockup, fine. But you can ask over and over and you're going to get the same answer from anyone who is telling you the truth: the elongated is better, the Toto is far superior to the Kohler, and only you will know whether that inch or two difference makes a difference, and the only way to know that short of buying both the round and the elongated toilets and returning one after you dry-fit them on the floor is to just mock-up where each will protrude to.
If you don't have the spec sheets already, I will be happy to posts links to the spec sheets in question.
Last edited by wjcandee; 12-02-2012 at 04:12 PM.