Brett Rader uses small scuds and Gbugs almost exclusively and his clients and him catches loads of big fish sight fishing.
Also, I read somewhere that the world record brown that Rip Collins caught had a whole belly full of scuds when they checked the stomach.
I know big browns eat smaller trout, but I believe they eat plenty of scuds and smaller stuff to go with there diet.
Brett had a picture of a 30" plus brownie that he guessed at about 20lbs on his site that he caught this fall on a scud or gbug pattern. The new state record was taken on a scud also.
I hear more big trout caught on smaller stuff than big stuff.