I've been using DIYPloneStyle to create custom installable skin products since.. err.. an early version, and the process always went like this:-

1. use the generator.py file to create a new product
2. install the skin product
3. Use the css_registry to deactivate most of the plone style sheets, so that I don't have to overide the styles in my custom CSS

The problem with this is that this can cause complications if there is any skin-switching capability, plus if you provide the skin to someone else to install you also have to send instructions to deactivate the appropriate stylesheets.

Today I downloaded the 2.1.2 version, and I was pleased to see that the blank skin product that it creates takes me to exactly the same starting point as I like to start from, i.e. all the plone default styles are deactivated. I say deactivated, but what I mean is there are blank public.css, plone.css etc files in the product, so when the product is installed, these have higher precedence than the ones in the plone layers. This is a much more convenient way to deal with overiding the styles, not sure why I didn't think of it before!