I was swamped on Friday and didn't have time to type out a full response:
For clarification, I've been using a 12voltguy harness for a few years - I just destroyed it when I ripped my exhaust off and melted a bunch of stuff under the 4Runner.
My issue with making my own is that the smallest available length of cable he used (Honeywell Genesis 1121 18/8c) comes on a 250' spool and it costs twice what his entire kit did. Then I gotta buy de-pinning tools, pin crimpers, more snake skin, vent tubing, etc. It'd end up being $400+ and many hours of harness fab that I just don't have.
Unfortunately, it looks like Yotamaster's retrofit kit is just about that much...