The best place to stock is in the free zone, Colon, Panama
. All manner of 'spirituous liqueurs' available. Minimum spend of $250(that was 18 months ago) but you can join with group of boats to make up order.
Fleur de Cana at $3.50 a bottle etc! No tastings so go knowing what you want. Friends stocked up and traded across the Pacific, bottles better as easier to barter with.
Cuban rum, only 'allowed' to take 10 bottles out of the country. You will be inspected each time you leave or return to your boat so hard to accumulate more.
Best rum imho Fleur de Cana followed by Appletons, all available in the free zone.
BTW most vendors will deliver to the dock
at Panama Canal
Yacht Club for a minimum fee.