I like grape and dark wines. I have done whites with oak, but you gotta watch it they can easily get over-oaked. Blueberry would be interesting to try with some oak, never done it. Same with perhaps blackberry.
Fruit wines, I like the fruit taste and not anything else.
Anybody use medium Hungarian Oak cubes with Blueberry? I have some in a carboy right now aging wandering to add some or not. Can you add them anytime before bottling?
I do not have any experience with blueberry, but im pretty sure you can add them in whenever you want. Just remember the oak factor will fade a little bit over time.