2017 EX Tail light wire channel access

[TXBikerGuy]

Objective:
Installing Skene P3 rear visibility/brake lights mounted along the sides of the license plate. I'd like to run the wires for the lights along the same route that the tail light wiring follows.

Easy enough to get the wire through the hole in the tail light mechanism and into the opening of the channel. But I'm not having success getting the wire all the way through to the other side (under the seat/top of the fender). Here's the channel under the fender.



Here's where the tail light wire comes out under the seat latching mechanism area.



Before I go further down this rabbit hole of taking off the fender, I thought I'd check here to see if anyone else has experience running a wire through this same channel/route. I'm assuming that if I follow the fender removal process, I'll see the opening of the metal channel and be able to run the wires. But, wondering if I have to do the complete fender removal or if there's a way to access it enough through some partial steps.

Thanks in advance for any help!