Again, its not going to happen, I don't know what you think the scenario is where you find yourself in thick fog and able to transition from forward flight to a hover in this sort of vis, its not going to happen, especially in a helicopter without all the 'bells and whistles'
I ask again as you have ignored the question, have you ever hovered in 50m vis, and do you actually know what 50m vis looks like? As if you did actually know what 50m vis looks like you would realise what utter toss you are spouting.
Erm Nige mentioned 50m as manageable for hover-taxiing rather than transitioning to the hover, and I agree with him (much as it would be a last resort - as he also said).
For the record, I have hover-taxied in 50m vis in mountainous terrain, and in 10m vis (estimated) at night over the sea. Not that either is remarkable, but this thread seems to have an appetite for stating credentials at the moment.