I demonstrate 'backward' autos, but as previously stated it is vital that you have sufficient altitude. (why only with a 25 knot headwind?) It really helps actually in gaining an understanding of sight pictures and setting the correct nose attitude to obtain the correct airspeed for the recovery. I teach in the 300, but have a fair amount of R22 time.
It is extremely important to develop a feel for the aircraft, rather than flying set numbers. Once you can recognise when the pitch of the nose is right to give you the correct airspeed then life will become much easier. Try not to focus too much on the airspeed indicator. Look at the trend of what it is doing and make slight adjustments as required.
One thing that I do as an instructor is to cover up the airspeed indicator with my hand and read out the airspeed as we descend. Therefore there is no point in the student looking inside, because there's nothing to see.
On the entry keep your eyes outside and keep the nose attitude constant, by using cyclic inputs. Don't let it drop as you will reduce your rotor RPM real fast.
Really listen to the transmission. It will tell you what the rotor RPM is doing. If the 'whine' gets louder you are gaining RPM, if it is getting quieter (or the horn comes on in the R22), then you are losing it. Collective inputs are made correspondingly. RPM goes up = collective goes up, RPM going down = collective going down. This becomes much more important when doing 90's and 180's.
Keep a visual lock on your spot. Look where you're going. The more time your eyes are outside, the easier it will become.
As far as flare height goes take great note of Rich Lee's post about the 300. DO NOT TRY AND FLY THE 300 LIKE AN R22!! Start the flare much higher and be more progressive.
Keep at it and it'll click. After a while it becomes a lot of fun trying to hit the same spot consistently from different altitudes and airspeeds.