In my experience, less toasting contributes more wood flavors with cherrywood. I've tried untoasted wood to charred all the way through, and all levels of toast in between. The untoasted is too woody for my taste in vodka, but it might be what you're looking for in your beer.
The medium-dark toast I like for flavoring my vodka has toasted wood outside with an untoasted core. The combination of the various levels of toasting combine to produce the complex praline-like flavor (think pecans and carmelized sugar, but not sweet).
FWIW the completely charred all the way through chunks contribute a charcoal-like flavor that hints of bourbon. Very one-note-song by itself, but intersting when combined with medium toasted chunks.
Lots of possibilties.