Boom length - measured from where exactly?

[awolf]

I'm trying to set my boom length to the recommended length for my sails, however I'm not sure where exactly I should be measuring to and from.

Here are some possibilities:
1. center of mast to inside of clew
2. end to end (outside of boom head to outside of clew)
3. innermost spot on mast head to innermost edge of clew area

Anyone know for sure?

[paulf.]

from the front of the mast to the clew touch point at the boom back end is the standard measurment.
P.