one of these blocks is an ounce...might be a bit hard to see one properly as they are wrapped up....but just to give you an idea.

I guess the only benefit of boiling soap in water is to get rid of some of the impurities....if the impurities are the type of shit that will give you a head ache then obviously it would be a better idea to wash them out....

I have no idea how much difference this will make to the weight....I haven't tried it myself, but again I guess it depends how much shit is in there that will disolve in water...im pretty sure some of the shit they put in it won't dissolve in water....

hope this helps a bit dude....
good luck