Good explanation Jim,
The helicopter designs are certainly a disconnect with the regulators modifying the aircraft regulations, rather than create a specific Cat H design, with specifics to helo operations. Trying to model the 'approach' based on, as you say, a runway, with a CAT A/B final approach speed of 90kts, an 8 second level segment, and a missed for a helodeck is not based in reality.
The plates that I referenced, shown the entire approach procedure with missed and hold, up to 12nm away from the helipad.....the charted obstacles have little value.
In an urban environment, you really have to go with a GPS approach, even if only a series of TF legs, to narrow the corridor down. At least you can have some assurance of the obstacle clearances, and the obstacle validation is much simpler to maintain.