[John N.]

It' varies from set to set. So to identify the specific measurements of your smidgen, dash, pinch set get a real 1/4 teaspoon and do the following

A 1/8 tsp should fill the ¼ tsp in 2 tries.
A 1/16 tsp in 4 tries.
A 1/32 tsp in 8 tries.

-John N.