#4's start flirting with speeds below what is needed for adequate penetration too early for me. Between 2,3 and 4, you're talking a big difference in speed at 40 yards. Diver are known to take shots and keep flying or hit the water and swim away. I prefer 3Ls over the decoys and early season, but when the birds are wary, having the range of 2's is what I prefer. 2's also can take a goose or duck, where I question 3's on geese. I shot a goose at about 40 yards twice with 3's and had witnesses. 2 solid hits and it kept flying up river and around a bend. About 45 minutes later, it appeared around the bend floating. About an hour later, it made it to us. That's just one example, but I usually would:t even have 3Ls in late in the year.