Id do that as two lots of about 20 grams, which is the dose I use for
two shots (ie one double). With the grinder adjusted fairly tight, Id
get it done pretty easily within five minutes at a not too vigorous
pace; quicker if you work at it. The time depends partly on how easy
it is to hoid the grinder; we have one thats round and waisted (a knee-
type design) where it is very easy to work up a fast grind, but another
rectangular box type is harder to grasp, not very comfortable, slower to use,
and needs frequent pauses.