When the going gets tough, the tough use 5 inch wacky rigged senkos on 6lb :) Seriously though, fish suspending in weeds are probably not in feeding mode. You may have better luck at Del Valle fishing a little deeper and fishing structure. Carolina rigging, or split shotting main lake points in 15-25 feet would be my first thing to try.

Have you tried Los Vaqueros? I want to get into the shoreline striper action there this fall, but I've only been there a few times.