Personally, depending on the razor I use both methods. I make sure when I use both hands the second hand does not rest on the razor but sits in front of the spine to stabilize it. it works for me but you do really have to be careful. I find even with my extra light touch if I have a razor that needs alot of honing unless I alter where on the spine the finger rests you will start to see a change in the bevel. So my answer is, for most people its best to use one handed honing. Its really like anything else you just have to work at it and it eventually works itself out. But having said that two handed is OK as long as you careful, very careful.