Oak Aged Amber - how much oak?

I recently visited my sister in London and tried a bunch of great beers that are either rare or unavailable here. One was Old Crafty Hen, a blend of Old Speckled Hen with a strong ale aged in oak barrels for years. It was great, light enough to be refreshing but with just enough oakiness for you to know it was a special brew. I’d like to try making an Oak Aged Amber ale myself and need some advice. I got some medium roast french oak chips, but how many oz should I put in the secondary? And should I put them in the keg when I keg, or would the longer they sit in there give more and more oakiness until the flavor is overwhelming? Also, I’ve thought about adding a small amount of bourbon to the final product to give another element to the beer, but I’ll see what the beer tastes like and experiment with a pint to see if I want to do it to the whole batch. Most recipes with oak or bourbon are darker beers so I don’t want to use the same quantities and have the oak be overwhelming. Any thoughts?

Here’s the recipe for reference:
6lbs amber LME
1lb belgian biscuit (I’ll do a mini-mash even though it’s only 1 pound of specialty grains)
(possibly 1-2oz of molasses)

.75oz Northern brewer for 60 mins
.5 oz tettnang for 20 mins
.5oz tettnang for 0 mins

yeast will be a starter of Wyeast American Ale harvested from a previous batch.

Add all of it and sample it after a couple weeks. The amount of time needed is not only dependent on other factors its also subjective. Chips impart the flavors quickest as they have the most surface area. I think Pietro can add to this but I think the optimal time is 4-6 weeks.

Only barrel treatment I have done was 3 oz. in a Belgian Quad. Threw in the primary for 10 days. Gave a nice oakiness that wasn’t overpowering. I did also soak them in 2 small (50ml) bottles of Maker’s Mark and that was probably one too many.