G'day Mykel
I made a batch at least a year ago & still using it. Base was some dark rum, Captain Morgan's I think but brand is immaterial. You do need some Bay rum oil ie Pimenta Racemosa. I got mine here :
Suppliers of Natural Essential Oils and Vegetable Oils - Australian Botanical Products but you can often get it on eBay if you strike out with abp. I added some Absolut Vanilla Vodka 50/50 so I got 2 bottles out of the process. & a bunch of EO's over time. Frankincense, clove oil, lime oil, etc You can just top it up as you go :) I even stuck a few orange rinds in the bottle for a few weeks haha. It's hard to muck it up. Just go easy with the EO's & use a good airtight bottle. All the goodies evaporate given half a chance. Probably about a tablespoon or 2 of Bay Rum oil is a good start.