I would try Fiocchi spreaders in this ole' German thing first.
I just hope they don't kick as hard as them Italian made Winchester Ranger 'Streukreuz' loads.
Unless you want real tight swarms I would say that plated 'Golden Pheasant' would be near the bottom of my try list.
I would go with those cheap Walmart 'Dove or Game' loads by Remington? first. Too bad you bought the dreadful 16ga because I get them 12ga Remington STS and Winchester Extra Light Target loads for my Sterlingworth at Walmart with some regularity.
PS. Ok, I would go with that mild und expensive RST stuff they are less expensive then visit to a dentist for fillin' replacements.