I perfer to take the opinion of Aerospace Engineers over yours.
Griffin wrote THE text book on the subject.
I'm willing to take the opinion of the folks who wrote the Planetary Society's Report like Skylab Astronaut Owen K. Garriott, John Garvey-CEO of Garvey Spacecraft Corporation, Astronaut Thomas D. Jones, Charles Kohlhase-Mission Design Manager for Voyager and other planetary missions, Astronaut Bruce McCandless II and Michael Griffin over yours.
Exactly what did you study in school and what degrees do you have?
BTW, as far as I can tell you made up this quote you posted.
"We started with what would be required for flights to Mars and worked backward"
Where does it come from? A link would be handy.