Rum to finish

So I promised a buddy of mine I'd do a special brew for his annual BeerBQ and after doing some searching he found a heavy banana hef finished with Rum. The recipe called for 750ml of Malibu Banana Rum and then 2 additional cups of some other rum - which to me seems like a lot of added booze - even over 5 gal of beer.

Anyone have any experience adding Rum right before bottling/kegging? If so amount/type you used?

I was thinking a cup or two right before bottling would add a bit of the flavor without totally killing all the flavor from the beer.

Thoughts?

Ive never tried adding straight rum, but did you ever try the Innis and Gunn Rum cask beer?

They just store it for a short time in old rum casks and the taste of rum dominates everything, you can hardly tell its beer. I'd imagine adding straight rum would probably have a similar effect?

that's what I'm trying to avoid...so I'm thinking 750ml bottle + 2 cups is probably out of control. I'm hoping the boards result in some feed back but if not I'm probably going to stick to 1 or 2 cups of a high quality rum...I'd rather go lower and have to add more next year than have the rum dominate the flavor.

Wont have a barrel for a bit...so its gonna have to be added right before bottling.

another thing to keep in mind that adding more alcohol may slow/stop carbonation by the yeast.

I'm 99% certain that I'll be kegging this one so I should alleviate that issue this time but very good point - didnt even think about the fact the yeast may not be able to take the added ABV and if I bottled I'd have flat brew

Yeah, the first thing I thought of was that much additional alcohol would kill the yeast... but if you're kegging it then no worries on that.