Put them right in the bourbon. I used chips on the stout i'm drinking now. I've read that the spirals impart better flavor and will try them next. Also, my friend told me that 16 oz. of bourbon was too much, so i strained some out of the soaking jar. i figure i put 8 oz. of bourbon in with the oak chips in my 5 gallon batch of imperial stout. This was not enough. Next time, I will use 16 oz. but, i like the bourbon flavor in my stout. with 8 only 8 oz., I barley notice it. Oh, and i used 4 oz. of oak chips.
I soaked the chips in the bourbon for two weeks while the beer was in the primary, then i left the oak chips in the secondary for two and a half weeks. The beer turned out great, but next time, I'll go three to four weeks and add more bourbon.