http://en.wikipedia.org/wiki/California_Proposition_19_(2010)
This I believe is the real place to go for understanding. Your link is a back handed attempt to make some one look foolish imo.
So according to this the bill states that I can carry and ounce and I can grow as much as I want in a 25 ft square area of my house or land that I own. Then it will be up to the local cities to decide if they want to license
places to sell it or allow people to smoke on their property. It will be up to the cities to decide if they want to allow you to carry more than an ounce.
So the actual vagueness of the bill stems from the fact that it throws it back to the cities to decide how they wish to handle it including taxing it.
Although you know the state is going to apply their own tax to it which will probably be 50 bucks an ounce.
So from what I read on this site while it does state an ounce as the starting point it isn't concrete. There is room to change it which obviously is going to happen once it's ratified.
Right now it's running 52 for 48 against from the polls I saw.