CBS is expected to roll out one of its new Wednesday comedies, Lorimar’s Bronson Pinchot vehicle “The Trouble With Larry,” in mid-August, paired with the Warner Bros. TV sitcom “Tall Hopes.”The web, which has stated plans to test a number of summer series in advance of their use during the traditional midseason, will delay “Larry’s” fall running mate “The Nanny” (TriStar) until later in the year and is expected to hold the Paramount action hour “South of Sunset”– scheduled for 9 p.m. Wednesdays — until after the web broadcasts the World Series in October. In the interim, CBS will put the one-hour reality show “How’d They Do That?” back in the Wednesday lead-off spot starting July 28, after the Steven Spielberg-Tim Burton animated series “Family Dog” concludes its four-week run. The new sitcoms will bow in the 8 o’clock hour Aug. 18. The three networks and Fox Broadcasting Co. have all been looking at staggered August-through-October new series premieres, seeking to generate sampling for the 38 newcomers that will arrive at the start of next season. ABC, for example, won’t premiere its Saturday comedy block of “George,”"Where I Live” and “The Paula Poundstone Show” until Oct. 30 (Daily Variety, July 2). “How’d They Do That?” performed well on Wednesday and will likely return to that slot during the season if the sitcoms falter. “The Trouble With Larry,” about a long-lost husband who suddenly returns home, has been revamped since its pilot, changing most of the cast with the exception of stars Pinchot and Courteney Cox.