"Eight to nine pounds is most popular in American skeet, in all gauges, because smoothly redundant swings are needed and hundreds of shells may be fired in one day. In the long run, it's easier to be better with a heavy gun. Since we can shoot with our shotguns pre-mounted, there is no rush getting them up to the shoulder, either."
"For dove hunting and sporting clays use, guns weighing from seven to eight pounds appear to be the most popular. Not having to walk nearly as far, the smoother swing and lower recoil of a heavier gun helps far more than it hurts. Most any weight gun can be used, but as far as I'm concerned any type of high volume shooting calls for a heavier, softer shooting gun."
"Most of the top shooters want a gun over eight pounds and a lot of winners go to ten-pound guns or even heavier. Like skeet, American trap shooting starts with the gun pre-mounted, and hundreds of shells may be fired in a day. Weight is not much of an issue, while long sighting planes (30-34 inch barrels are typical) and smooth swings rule the day."
"An easy way to test shotgun weight is just to shoot a few crossers at the local skeet field or sporting clays course. If you need to consciously force your scattergun to keep swinging, you have probably gone a bit too far in the lightweight, whippy, stutter swing direction."
I use a Remington Premier Comp gun for skeet and sporting clays(relatively light). I use a SKB Combo gun for trap (a little on the heavy side).