If anyone is concerned with over oaking, check out oak beans. I picked some StaVin oak beans up at a home brew shop because that was all the had, but am glad I did. Here is some info on them, and they look just like regular oak cubes.
"StaVin's oak beans are made with three year air dried American oak from Missouri, 2 year air dried French oak from the center of France (Cognac) and two year seasoned European oak from Hungary.
The oak they select matches the same quality requirements as staves which are used for premium wine barrels. The StaVin oak bean is a one-of-a-kind invention that is unparalleled in the industry today.
Staves are traditionally fire toasted using methods coopers have perfected over the centuries. Experienced production personnel pay careful attention to thermal parameters, ensuring full heat penetration for specific toast levels.
Once toasted, a percentage of staves go into full stave systems for barrels and tanks, while others are processed by a proprietary bean machine. This machine cuts the staves into beans and sends them through a stainless mesh to eliminate any excess particles.
The minimum recommended contact time for barrel quality extraction is eight weeks, using a ratio of 1 to 2 pounds per sixty gallons (2 - 2.6 oz per 5 gallons) of wine. The StaVin oak bean has a useful life of eight to ten months, at which time it is fully extracted.
The oak bean, which is more dense than oak chips or oak powder, produces less phenolics- giving your wine more rounded, complex flavors which will enhance your wines. We are proud to be a distributor of Stavin Oak Beans."