I finally got this red and yellow vertex map to look like yours. I had to start over in a new document...whatever was going on the selection was jumping to just a black and white selection and wasnt growing. after gowing through this step by step finally gave up and made a new prject with a new sphere and finally the red and yellow selections showed up. I know I am not crazy!!! but I know how starting a new project and get rid of some setting unbekinownst to me that was fucking this process all up!!! so anyone struggling to make this seemingly basic task work...open a new project start over..LOL
after you set the vertex weight to zero and click on the vertex map...in R23 is doesnt automatically give you the paint tool.. you have to manually select it or hit space bar twice toggle to it. then you can paint the yellow selections! ugh! finally!! LOL