I've tried lately with a single shot 30" barrel full choke 16. Haven't killed yet, but I also don't take it every day. I think it has a killing pattern at about 30 yards, I don't want to go any further than that.
I used Remington Express High Brass 1-1/8oz number 6s. I'm sure the federal and Winchester 1-1/8oz high brass number 6 will do just as good. Shot size is probably more about preference than anything. I myself like 6s, they have always patterned better at short and long distances. I have used 5s some. Just never been a fan of 4s although I'm sure they work just fine.
TSS throws the best patterns these days. It's not that I'm against TSS, I just don't want to use them in my old 16 because to me it isn't "old school" if you use TSS to make your range 10-15 more yards.