A month or so ago, I told a then friend in Marble Hll, MO that I was changing my hummer sugar feeders from four to one to six to one.  He sent me a blistering response that I was doing them  a terrible thing.  But guess what?  According to the 2010 Audubon book "North American Bird Feeder Guide", page 31, use the 4/1 to attract them, then switch to 6/1 once they have found the feeders.  It will better for their kidneys, and give them the water that they need.
Tom Creley
The Audubon Society of Missouri's Wild Bird Discussion Forum
List archives: https://po.missouri.edu/archives/mobirds-l.html