Look for precision, or starret footlong feeler guages, come as individual parts in the specific dimension you chose.
For starters, try ordering a pieces in .020" .025" and .030" much better than having those pieces of .009 that are too thick for shim and too thin for picks left over, (however, a mini knife type can be made of anything around .010" and probably the nine thousands inch as well) Mini knife is the opener for sesamee and its master and other brands knockoffs. Ask dmux, hes got a real tiny one
by ordering specific thicknesses, you can get a number of them in the same size and now have to take a complete range of sizes which come in the mechanics set. However if you do order the mechanics set, there is a type that has an open slot down the middle that I have used to make double sided picks with a separation down the middle.