Normal hover height during instruction in an R22 is an interesting one. Its a long time since I flew the R22, but I used to be (slightly) criticised in general discussions with other instructors for hovering at, and requesting that students hover at the AFM recommended hover height (can't remember what it was any more).
Other instructors used to remark how low my students hovered. Their argument was that with a low time student the risk of them touching the ground going sideways was a greater risk than being a bit high, in the event of an engine failure in the hover.
Any thoughts?