[NTG-context] Is setupspacing configurable？

I am setting up the space after a period.

From the context manual, it is said that "Default a space is placed after a period that ends a sentence. In some countries it is custom to stretch the space after a period. ... One can however change this spacing

\setupspacing[...] ...broad packed if this argument is set as 'broad', what is the exact space? Let's say I want two spaces after the period, how to set this?