When I removed the headlight trim ring, headlight and headlight mounting bracket install the Daymaker parts it was simple to reach up inside on the right (throttle) side of the trees and unplug the connectors and put the HD harness in.
If you remove the headlight trim ring and headlight (refer to the repair manual if unsure how to do it) you should be able to reach in there to install the harness without taking the fairing halves apart.
Removing the Head Light was my next question , so thanks for expanding on the installation without taking the Fairing off

When I connected the switch wires into the harness plug behind the switch housing I manage to install them without taking anything off.
Here is what I did,
1, Removed switch plug on clutch side of switch housing to allow for installation of passing lamp switch.
2, Screw passing lamp switch in place of removed switch plug.
3, Run switch wires to throttle side of switch housing.
4, Bend metal tab on the throttle side behind the switch housing that holds the harness from dropping freeing up harness and exposing harness socket.
5, Pulled the harness socket out just enough to disconnect it.
6, Connected the passing lamp wires into harness socket.
7, Connect harness sockets together tucking wires up behind switch housing together with harness sockets.
8, Secure harness into place with metal tab.
It was a bit fiddly but well worth it without removing other parts.
What I am not sure about is,
With the optional harness that allows passing lamps to be switched on with Low and High beam does it plug into the harness sockets behind the switch housing.
For example, disconnect harness and bridge optional harness between the original sockets.
The instruction are not that clear and only show the installation by removing the outer fairing.