It isn’t just the Lensman series but also the Skylark series by E.E. Doc Smith that inspired Lucas.
I’m also convinced he read Edmund Hamilton and Leigh Brackett.
I know he read Dune, Galactic Patrol, at least the first trilogy of Burroughs Mars tales and the Foundation trilogy.
He was a big fan of comic magazines and newspaper comics. He liked Hal Foster, Alex Raymond. Wally Wood, Al Williamson and Frank Frazetta.