Sounds like a big range in sizes will do - #4-4/0. You will find a guy like Lefty Kreh who says that size in surface flies is not so important becaus the ruckus made by the bug disguises the size. I will go with that up to a point. Last season the overachieving bluegills in my favorite lake woouldn't leave my #4 popper alone. I switched to a Stealth Bomber on a #2 hook. The crappie liked it and the bluegills continued to hit it. Next time out I used a Lefty's Bug on a 2/0 3x hook about 4 inches long including tail. After a cast or two a 7" gill hooked up even though the bug had a double wire weed guard. My rule of thumb for lake bass is any fly should be at least 3 inches long with 4 or more preferred. I do not think a bass will not take a #6 or smaller offering; I just want something that the small fry will leave alone.