You SHOULD use 40 cloves - this needs to be a very strong-flavored syrup with the desired (and often required) depth of flavor and complexity of character. That's exactly why it is used in relatively small quantities in classic cocktails. It all balances out very nicely in the finished syrup, so don't worry about the 40 cloves. It's the right amount of cloves for how this syrup is intended to be experienced and used. Also, DO NOT USE Bacardi 151 because it is a low-grade comparatively harsh-tasting 151 which should be avoided. Use, instead, the recommended and much more neutral Wray & Nephew Overproof Rum which will have high enough alcohol content to extract the flavors and oils from the ingredients without introducing any harsh (low-grade) flavors into the falernum. I have made many batches of falernum now, and these suggestions are the result of what I have learned.