I have to say this is a VERY potent mix. If you haven't heard the song "Caribou Lou", you might be missing the point a little bit. It's by a prolific underground MC called, "Tech N9ne". If you ever had powerful stuff like a proof over 150, you'll notice how potent this ish is.
There a few recipes including more rum and more juice. And other requiring a bit less rum and a bit less juice. Either way, it does not really matter because you are drinking some super strong ish. It's potent. I have two different ways of making the Caribou Lou below, and also the official song so you can see the inspiration.