Rookie writer/helmer David O’Neill, who recently landed Charlie Sheen as a co-star and Cary Elwes and Amanda Plummer in cameos for his big-screen adaptation of Jack London’s novel “Martin Eden,” has been signed by the William Morris Agency. O’Neill, who also powwow’d with Intl.Creative Management and United Talent Agency, will be repped by WMA motion picture VP Jim Crabbe and agents Jennifer Craig, Jeff Field and Beth Holden. Lead casting is near completion. The Saturday premiere of “Culture Clash” on KTTV was rated No. 1 at 7 p.m. by Nielsen, with a 6.4 rating, 15 share. The show, which is in the running for a syndicated or network launch, improved the time-period standings of the aging rerun “Three’s Company” (2.2/6) by more than 66% in rating and 60% in share. It also improved its lead-in, “I Love Lucy” (4.1/10), by more than 36% in rating and 33% in share. In Arbitron, “Culture Clash” earned a 5.9/13 to finish No. 2 in the period behind KABC-TV’s “Jeopardy!” (7.2/16).