I must admit I've always used the slightest of light machine oil on the balls prior to installation and have never had an issue. I guess what I call slight is merely a oily rags worth with the balls rolled around inside the rag which would only put a film on them and not have them wet, nothing more.
Cheers, BB
I live a 24 Hour lifestyle, but every now and again I seem to fall asleep, well at least that's what my wife tells me.