I recently added oak soaked in bourbon (1month soaked) to a RIS. I used 1oz of soaked cubes and .25oz of fresh cubes. I chose not to add the bourbon, but kept it in a jar to add later if needed. I ended up keeping the oak in for about 2 months. When i reached approximately what i wanted from the oak, i left it in another 2 weeks. I did this to account for some fading since the beer will age another 3-6 months before serving.
I brew lots of beer.