The short/sweet answer (at least for me) is to shoot the 2-3/4" Winchester Super-X (silver box) shells, especially those manufactured in Australia (need to read the small print, but at this point I don't bother). Come only in 1 oz. loads, only #8 and #6, usually available at K-Mart, among other places. Lots of guys on the SSM BBS who shoot old 16's like this shell. It is my preferred shell for everything from my Parker VHE 16 to my Smith Ideal 16 to my short-chambered Win Mod 12 16. Cycles fine in the old Mod 12, no ejection problems. It is noticeably softer shooting than similar (promo and field) loads from Fed and Rem.

B&P also makes a nice light/short load for 16's, but you can't buy them at K-Mart.