As any SBIFF regular can tell you, the Screenwriter’s Panel, usually occurring during a late weekend morning in the Lobero Theatre, is both one of the festival’s best and most overlooked offerings. Drawing a devoted following each year, the panel attracts a wellspring of talent and its discussions make for the most casual, lively and candid event at the festival.

This year’s panel consisted of Guillermo Arriaga (“Babel,” “21 Grams”), Peter Morgan (“The Queen,” “The Last King of Scotland”), Michael Arndt (“Little Miss Sunshine”), Jason Reitman (“Thank You for Smoking”), Aline Brosh McKenna (“The Devil Wears Prada”) and Todd Field (“Little Children”). The conversation was moderated by Anne Thompson of the Hollywood Reporter.

It’s hard to capture so briefly the diversity and the spark of this year’s panel and its members. Their accomplishments and personalities were as diverse as their methods. Arriaga, a former novelist, took two years to write his most recent screenplay, writing it almost completely a priori. Morgan is, in his words a “research fanatic,” and spent three weeks researching before his first draft of “The Queen,” traveling across Britain uncovering all he could about the royal family. Reitman adapted “Thank You for Smoking” from a Christopher Buckley novel, quickly spinning his screenplay from a copy of the book filled with Post-it Notes.

“My style is similar to Guillermo’s, but with less talent and skill,” Reitman quipped.

The writers, despite the differing lengths of their creative processes, both agreed on the 80 percent landmark of the screenwriting process, at which the screenplay reaches its final stages and the truly difficult work begins. As “Little Miss Sunshine” scribe Arndt explained:

“You eventually reach the 80 percent mark … you hit the limits of your initial conception. Hollywood is awash with screenplays left at 80 percent.”

The solution? Rewriting, revision and research. The panel consented that though the final 20 percent is the most arduous part of the process, it is also the most rewarding, where some of the finest scenes are created and the film finally comes into its own.

“The best advice for a writer? Finish what you start,” said Arriaga.

“Like the Keebler Elves say, ‘You can’t rush richness!’ explainedArndt.

“If you remember one thing from today, remember that,” Reitman added.