For next time, I would recommend getting a really flavorful cut. Maybe brisket. Or even tongue, which is very flavorful, cheap, and the texture won't matter anyways. I would do a smaller batch so that you don't need quite so much beef, maybe just a gallon or two.
First I would slow braise it, collecting the juices "au jus" which will be skimmed and added to the bourbon. Then I would cut it into half-inch cubes and brown then nicely in a pan (cast iron would be best, but as long as it's NOT no-stick, it'll do) with a bit of the au jus and a bit of butter - clarified butter/Indian "ghee" (which is the best option, and is basically prepackaged clarified butter, sometimes browned a bit to give a wonderful "nutty" character to it. One the cubes are nice and browned, add as much of the beef as you can (in half-inch cubes!!) to a mixture of the bourbon and juices for a few weeks, and then take it out, smushing the beef a bit to get as much liquid out as you can.
Then, add the bourbon/au jus to the fermentor at that point, after the primary has finished fermentation, the beef itself, can be used for whatever cooking purpose you want, as they won't be yeasty or fermented - if you're ready to bottle and a tad more beef flavor is desired, some packets or cubes of beef bouillon powder would be great. Try it in half of a pint glass (one cup) to see what the right level is to make it taste beefy but not too beefy, and then scale it up for the whole batch.
I think this would be a foolproof way of maximizing the beer flavor. Ask me if you have any questions or concerns.