You may want to look at the FAA doc 8260.42B, which is specific to helicopter operations, so it wades through quite a bit.
Its also allows for Vmini to 70kts, rather than the Class A 90kts.
This is the RNP criteria, so while you can use the containments as allowed, much of that is useless.
Figure 4-5 will at least give the surveyors some guidance on the visual segment parameters.
Another option is to use the PinS type approach for the helipads. This would allow parameters for a surveyed corridor.
The FAA has many
helo plates in their procedures database for you to review, the
MOS 173 from Australia, has plate templates as well.
so I want to pictorially represent the height of obstacles within certain radius of the centre of the pad so that crews can elect the safest type of departure for the given environment.
you would use the standard surfaces that are shown from the end of a runway, but as a circle, there is the 50:1, 34:1, 20:1 for certain distances.
Here is the
US Army Helo example
You would probably want to sector this, as to not try to survey too much. I would start with the MET data first for the location, and get the typical prevailing wind directions are a first look...
(you can skype me as well)