Fireball, are you shooting blues or ruffed grouse? I've shot a lot (well, keep in mind that they aren't easy if you wingshoot them....)of ruffs, and a few blues. Ruffs tend to be closer to the gun when they flush and you'll want a bigger pattern at close range, so I'd say 7 1/2 or 8 lead shot, and a 3" shell to get the most shot a .410 can handle.
Blues tend to flush high and far and with a .410 I'd use 6s. And I hope you are one hell of a wingshot--they aren't easy even with a 12, as you probably know.
Some "experts" say a .410 shouldn't be used for wingshooting at all. I've seen some ACTUAL experts kill just about all upland birds except turkeys with a .410. But they were real experts--expert wingshots, careful gun choice, and with specifically developed handloads were based on a lot of experience and knowledge with shotguns in general and .410s in particular. (I stick to cottontails, quail, and clays with MY .410s....).
Beautiful gun; have fun!
(P.S. If you don't get detailed answers on the use of steel in that Salvinelli, I'd suggest you ask over on the "Double Shotguns" forum of the
www.doublegunshot.com/BBS site. California is mandating steel shot for upland in a couple of years and I suspect there is a lot of experimentation going on among the .410 crowd!).
