In it you will find a whirlwind of information (and a rousing fight) which basically talks about the scientific improbability of cocoa butter being able to be absorbed by our body. I know Edgar Casey was a proponent of cocoa butter, but if it worked like he said we would all have a much easier time of NBE.
I also know that many women swear by it and I think the reason is that 1. It smells nice, like chocolate... and who would hate that? and 2. It is a great lubricant for massage which does promote breast growth. and finally 3. It can act as a moisture barrier which can enhance hydration to the skin.
Use cocoa butter if you like it. It certainly will not be a negative thing to NBE, but don't assign it magical powers beyond what is scientifically valid.
As far as the form - any form is good as long as the other ingredients are not harmful. Many have used just the pure form, which is cheaper, but you have to heat it to make it liquid.
I used cocoa butter for years and I never got a lick of growth out of it. It's also expensive and it smells bad ( the pure kind that is). I do have one thing to thank cocoa butter for though, it's how I found this forum. I was looking up information on CB and breast enlargement and just happened upon this site. So, I guess cocoa butter does enlarge breasts in it's own roundabout way!