From the source (Denizen Rum): a little more background on the blend that makes up Denizen Merchant's Reserve, and its relation to the Trader Vic's Mai Tai. It's like bonus material for episode 7 and episode 30 of this here show.

“While many brands do not tend to tout the process of blending that takes place across the industry to varying degrees, there have been a breadth of new rum brands in recent years that celebrate a resurgence of old style rums such as the colonial American style of Medford rum being produced once again in New England and also rums that have a more international provenance, being a blend of styles from different islands.”