I use IBC silk pins #215004 from Clotilde: .50mm, 1 1/4", 500 to a box.
http://www.clotilde.com
They were recommended years ago by Jean Biddick (by far the best most accurate piecer I've ever seen) as the only pins your machine could safely sew over.
Everyone who takes a few from me to try at workshops or retreats usually then buys a box.
You can see Jean's work on her Gallery page
http://www.jeanbiddick.com