I've tried a French Oak Stave in an Old Ale for 2 weeks in secondary. Last Quad I did, I used 2oz of French Oak chips, I toasted at 180* for 20 mins, drowned 'em in 4oz of Maple Bourbon for 2 weeks, then just the cubes into the carboy for 10 days, gently shaking the carboy once a day just enough to move the beer around, but not enough to splash. Prepare to let it age a few months to allow that oaky flavor to mellow and really blend into the beer good.