Update on my recipe...I used lightly toasted oak chips from the HBS intended for wine. The recipe called for 2.5oz of oak cubes in the secondary for 5g, but I used 3.5oz since that's what came in the packet. After 1w primary, 2w secondary, and 12 days in the bottle the beer is well carbonated and definitely has an oaky taste. Not too much, but assertive. One thing I don't like is a light tannin astringency in the aftertaste which I assume came from the oak since I didn't taste it when racking to secondary. I think I used too much oak, but I also think the astringency is so light that there's the potential for it to age out of the beer some. My wife doesn't even notice it. It's definitely not grain husk tannin, more like the tannins found in wine which aren't necessarily bad in wine but I didn't want in my beer.
Another thing...I think a surface area measurement would be better than mass as far as the oak cubes go, i.e., 100 cubic inches vs 2.5oz. It's really the surface area that determines how much oaky flavor you'll get, not the weight. A 2.5oz monolithic cube would contribute a lot less oak flavor than 2.5oz of cubelettes 3/8" on a side (like mine).