Tweedles you have a lot of height, around 1000' feet or so you might stand a chance of getting into forward flight but if you watch the video of the yellow wessex, he tries this but cannot gain sufficient airspeed and he was doing around 60 kts at the time of the failure.
I do not believe there is a rule of thumb for this manoeuvre but hovering at heights up to about 500' it may be worth lowering the lever sufficiently to get a manageable rate of descent and a manageable rate of rotation but there are no guarantees and it will vary from type to type. Having a slab sided tail boom like the S58 will help as it creates a lot of drag and reduces the rate of rotation a bit. You have so little control in this situation you can only hope you get to a position where you can chop the throttles and carry out a hover EOL.