For what it is worth...I have tried multiple picks and have settled on the Golden Gate mandolin picks. They are rounded and three sided...3 picks in one. THey provide an excellent tone and are relatively inexpensive. You can get them on eBay by typing in Golden Gate mandolin picks in the search engine.
Also, Long Hollow Leather (longhollowleather.com) makes a great pick holder comparable to the Jazzmando pick holder...They are the makers of the LHL "Softie" mandolin strap that is, IMHO, one of the best mandolin straps on the market.
2004 Weber Yellowstone Custom Mandolin
1976 Alvarez "The Alvarez" F Style Mandolin
1998 Guild D-40AB Westerly
1997 Martin D-35
1982 Takamine EF-400SC 12 String
1976 Takamine F-360SD Sunburst
1977 Fender F-65