Take the best practices and methods of each, mix and modify them in a way that's most appropriate for your niche, competition, product, short-term or long-term plans, specific goals, etc. Then just full steam ahead. Black or white, who cares. I don't really think you can really understand the depths of seo unless you can practice both as is needed.
An example of this would be to throw quickly ranking short term sites into 20 niches, find out what converts the best and build a more white-hat authority site in that niche. This is a really simplistic example but the point is you lose so many options when you limit yourself to one "hat".
unless it's a rainbow hat?