I've always used high viscosity oils such as auto gear lube, made my own with a mix of grease and motor oil to make a concoction that just barely drips and also found that Chain-L lube or Phils Tenacious works perfectly. IME too thick of a lube such as straight greases will make it difficult for the pawls to engage and too thin tends to seep through the seals in warm temps for Shimano FH's.