I’ve got the presentation that Dallas Bienhoff gave in Long Beach last week that implicitly demonstrated the lack of need for a heavy lifter.
Note the element weights on page 6. The heaviest item is the depot at twenty tons, but that could go up in three flights. After that is the lander, at twelve tons. That sets the minimum throw weight for the launcher. It’s about ten percent of the eventual capability of the SLS.
[Update a few minutes later]
What’s funny is that the paper doesn’t just bury the lede — it leaves it out entirely. Note that nowhere in it, including the final chart describing the benefits quantitatively, does the phrase “heavy lift” appear. Because Boeing is not allowed to actually say that heavy-lift isn’t needed, even if that’s what their own analysis shows.