I spent 2 hours trying to get a basin wrench on the nut, but it is two wide,
too short, and too obstructed.

Moen finally got back to me by sending me a PDF of the faucet.

I emailed them again and said I don't need a diagram, I need information on
the wrench required!

They called and said they will mail me a free wrench (after first telling me
the 7200 didn't need one.)

Alls well that ends well.