Gonna try to brew a FW Velvet Merlin clone

So I found a recipe for a Velvet Merlin clone here on HBT and I'm going to brew it up in a couple of weeks. The recipe looks good but I was wondering - since they do some whiskey barrel aging with this beer and I don't have a whiskey barrel handy, would adding a few ounces of whiskey to the fermenter give it a similar taste? If so, how much would you add to 5 gallons and when? Seems to me like it would be just a few ounces at the end of fermentation but I defer to those who have gone there before...

That's pretty much the way to do it, for reference Denny's Bourbon Vanilla Porter uses ~1-1.75 cups of bourbon for a 5 gallon batch.
http://www.brew365.com/beer_dennys_bourbon_vanilla_porter.php