Interesting reading, but a few things come to mind:
1 - It seems everyone seems hugely concerned about the H/V curve, and the shaded 'avoid' area. (where ag, mustering and sling pilots live just about all day long...)
In my opinion, for this type of approach you simply have to accept that you will be inside the H/V curve for a fair period of time. The chances of the engine failing during this period are FAR less than the pilot flying a bad approach and winding up in VRS or running out of power at the bottom and hitting hard. Prioritise your risk: Why fly an approach profile to try and stay out of the H/V curve (and minimise an already minimal risk) while doing so MAY greatly increase the far more significant possibility of VRS or having insufficient power available? Be aware of the H/V curve and don't fly in it if you don't have to, but don't be hung up on it.
2 - Second big school of thought is unloading the tail rotor by having the crosswind on the appropriate side.
While I don't disagree with the concept, you shouldn't be flying this approach under the given conditions if you don't have sufficient power available, regardless of where the crosswind is from. So why be concerned about unloading your tail rotor and in doing so select an approach path that may in fact be less suitable due to obstacles, angle, head wind component or forced landing areas? (As an aside: Say you have the wind from the left to help reduce TR demand (non French). IF the engine does happen to let go, its going to yaw left and into the wind. While this might seem great, you are going to end up completely crossed up to the original approach path, in auto sideways with a new view, close to the ground and trying to work a new plan with no time and little speed. Try it (with an instructor): set up high with very little forward speed, lots of power and a brisk left crosswind and chop the throttle. It will give you an idea of how pear shaped you can get.)
3 - No one has talked about doing an in flight power check to assure you have power available to do this approach at the time.
Yes, check the performance graphs. But what if the ambient conditions are different, or you've got an extra person on board etc? I strongly suggest to do your homework and develop an in flight procedure that will fairly accurately tell you what your HIGE and HOGE power required will be under the conditions. Make sure you've got what you need to do the job.
I personally don't like the idea of an approach to a point and then descend vertically, unless the area is so confined that you have no other choice. Aside from the increased risk of obstacle strikes, it will demand more power than flying a constant, albeit steep, angle all the way to the ground. No problem IF you have HOGE power available.
It takes less power to descend than it does to hold height for a given speed, and if you hold your angle to a ground effect hover you will always fly the approach with less power.
As a general rule with all other factors equal, I would take the best line in that gave me the shallowest angle within the confines of acceptable wind and fly a constant angle approach all the way to the hover.
An approach angle is a combination of ROD (towards the ground) and forward speed (over the ground). So if you have to do it crosswind or downwind, then make sure you hold your angle, keep it slow by reference to ground speed and your ROD won't be a problem.
All this ASI talk, how then do you make an approach if your ASI has failed?
That's gotta be the longest ramble I've done, hope it makes sense!