The supervision aspect is even harder where flying your own ship.
With club/ school machines the supervision comes (with good clubs/ schools) as part of the package.
So how to achieve it and stay safe when an owner?
Some of it has to be self regulation/ self briefing. If you study the stats for R44 accidents in the UK 'since records began' it has been rare for an owner to wreak their own machine. Usually it is somebody else doing it for them ... (2 out of 12 to Jan 04).