Substitutes:

• Bourbon: You can use rye whiskey for a spicier kick if you don't have bourbon. We've also tried it with brandy (more specifically Cognac), which adds a different but pleasant flavor profile.
• Cointreau: Any type of orange liqueur, such as dry curaçao for example, can be used to make this cocktail. For a lighter version, you can use orange peel syrup as a substitute. To make your own syrup, mix together 1 part white sugar and 1 part water over low heat. Stir well to dissolve the sugar, remove from the heat, and add orange peels to the syrup. Let the mixture cool down to temperature, transfer to an airtight container, and let it infuse in the fridge for at least one day. When ready to use, strain to remove the peels and store in the fridge after use.
• Sweet Vermouth: Any kind of red vermouth can be used for this recipe. You could also try a fortified wine like port or sherry (Oloroso, Palo Cortado, or Pedro Ximenez for example) for a different flavor profile. Dry vermouth can also be used for a less sweet cocktail, although it will certainly result in quite a different-tasting cocktail.
• Fresh Lemon Juice: Bottled lemon juice can work without fresh lemons, but fresh is always best for that vibrant citrus note. Another option is to use fresh lime juice for a slightly different citrus kick.

Making a Pitcher of Man O' War:

• Scale: To make a pitcher that serves 8, multiply all the ingredients by 8. That would be 12 oz of bourbon, 4 oz of Cointreau, 4 oz of sweet vermouth, and 4 oz of fresh lemon juice.
• Mix: In a large pitcher, combine the bourbon, Cointreau, sweet vermouth, and lemon juice. Add ice and stir well.
• Serve: Strain to remove the ice, serve immediately into chilled coupe glasses and garnish each glass with a lemon peel and a maraschino cherry. If you have some leftovers, be sure to keep it in the fridge (make sure no ice cubes are left inside) in an airtight container. Give it a taste and stir a bit more if you feel like more dilution is necessary.