So of the two responses it looks like some folks add oak before fermentation and some add after.
Response #3 is do both. Commercial wineries often do barrel fermentation and then age in oak barrels.
I add oak chips during fermentation, at a rate higher than is suggested for aging oak. As per
@jgmillr1's suggestion, I'm thinking about trying granulated oak instead of chips.
My barrel is 11 yo and it has no remaining oak character to impart so I use oak cubes. I like them, but they're harder to get out of the barrel than staves or spirals.
However, I will be experimenting with
Next Level Oak's wine stix this fall. I have an American oak kit with a carboy stopper, and am considering the barrel stopper when it becomes available. Mike (owner) has French and Hungarian wood coming in by ship, so those will be available later this fall.