I recently acquired a very nice early 20ga Savage SW (with Philly characteristics--smaller, pointed forend and PG cap), 28" barrels. Original constrictions were a tight Mod and well beyond Full. I had them opened to about skeet and LM. In my case, it will be my main grouse and woodcock gun, and from my experience with early season prairie grouse (leaving for ND in a little over a week), it will work fine on them as well. If I were a dove hunter, I might have left it tighter. But I'm not, so I didn't.
Some folks forget that while open chokes do give you more margin for error when you shoot, if you're doing a lot of close range shooting (like grouse and woodcock, especially early season), they also reduce the chances that you're going to destroy birds shot in the 10-15 yard range. And shots that close can be more the rule than the exception, if you're hunting woods birds while most of the leaves are still on the trees.
