Interesting...I think shaking it is a good thing. I make my own cordials and they too
direct you to shake it up.
Not that you'd want to burn off the alcohol, but I wonder if the flavor would have imparted stronger if you heated it up a bit, then put the bacon & fat in there? Like when you infuse a cream or a milk base, you heat it up.
Also, as I found when I was making bacon toffee and the bacon ice cream, the bacon matters. You want an assertive, big flavored bacon. I recently got a double-smoked bacon from Jensen's smokehouse and it's amazing what a difference it makes.