I'm currently installing drywall in a 20x18 (approx.) room, and I am
planning on finishing the seams with fiberglass mesh tape (except the
inside corners, which will use steel-reinforced paper; there are no
outside corners in the room). Fiberglass mesh tape requires
setting-type joint compound for the first coat. Fortunately, one such
compound (Sheetrock Easy Sand, in various setting timeframes) is
available at the local big-box hardware stores. Unfortunately, the
packaging only lists the mixing proportions for mixing the entire bag
at once! Needless to say, I don't need 18 pounds of compound to finish
this small of an area. However, scaling down the "recipe" poses a
problem because I do not have a weighing device that is accurate enough
to weigh the joint compound. What I need is the mixing proportions by
volume (in other words, the ratio of volume of powdered compound to
volume of water). What proportions are generally used by people who
have worked with this compound? I wasn't able to find any information
on this on Sheetrock's website.

Also, do you need to use a drill attachment to mix the compound, or can
you do this effectively with a wooden stick or dowel?

Thanks in advance.