Hi Dog.
Both the Whierauch and the Twink work well on the S200, tried both.
The 10 shot conversion is a dream to use, is it worth the money?, I think so.
Pellet wise, as Tony said, AA go well and are a good starting point to try.
Mine is .177 and I shoot AA with good results, that good, I have not tried any other type in her.
Keep the bolt well oiled too ( 3in 1 )
ATB.
Bill.