Just installed a Moen kitchen faucet (model 87666) on a sink with three holes. The escutcheon & gasket kit was used to cover each extra hole on either side of the faucet. Tightened down everything pretty well but I'm getting a leak through one of the extra holes underneath into the area below the sink. Is there a plug that I'm supposed to put in the extra holes? A web search for such an item shows some decorative covers that just snap in place, but also some that have a gasket and are tightened from underneath to make a seal. Moen just suggested to use some putty between the gasket and the sink which they never mentioned in the instructions... Should I use putty, or silicone?