And obviously you did read my posts and I did not read yours very thoroughly...
To say that Boromir fell off the wagon in a heartbeat negates why he came to Rivendell in the first place.
He came looking for help in the defense of Gondor. He thought he was entitled to that help because only Rohan was helping in the defense of Middle Earth against Mordor.
When he saw the ring, his eyes glinted so Tolkien wrote...
To me (and everything here is opinion so there really is no right or wrong as in a test... if you believe Boromir fell off the wagon, that's fine...) Boromir came looking for help, and the moment the ring appeared and was identified as the one ring... Boromir understood it to be a weapon.