First, let me confess that I've never had the actual Mojito cocktail. I was curious about the ingredients so I looked up the recipe... the combination sounded good, so I ordered some flavorings and after a couple of test batches here's what resulted:
1.0ml PA Jamaican Rum
0.6ml PA Brown Sugar
0.2ml PA Lime
1 drop PA Spearmint (or slightly less)
1 drop EZ-Sweetz sweetener
4.2 ml VG base, 80% VG / 20% distilled water*
The Spearmint is really strong. I advise cutting a small quantity to 25% strength with PGA and then adding about 3 drops of that mixture unless you want the spearmint to stand out.
Be careful with the Lime too, it's also potent.
*could try using Dark Rum liquor in place of distilled water for a more authentic taste and possibly better throat hit.