This is great feedback and discourse. Thanks everyone.
Bob makes an undisputable and compelling argument:
Originally Posted by n982sx
For my last point, I have now flown my airplane with Van's standard wiring and have had no issues with any of the wiring.
However, I can't just go against all manufacturer recommendations I can find and sleep at night, so Carl most closely aligns with my personal plans. Based on posts, quite a few people are getting warnings or outright failures of the GMU when mounted in the wing with stock wiring harnesses. I would rather be proactive.
Running the ground wire through the wing as pointed out by Bob was an afterthough by Stein / Vans, and I'm still really confused why they would run shielded for the nav/strobe to the tail but NOT when going past their recommended location for the magnetometer. It's such a trivial change.
Additionally, it appears that a heated pitot (which I am installing) has the potential to cause conflict when placed in the left wing.
As a result, for anyone curious, I plan to use the stock Vans harness in the tailcone on the left side only. I'll place the OAT in the left wing, with all high-power active equipment (pitot, ap servo, trim) in the right wing away from the magnetometer. Wing lighting will be shielded (at least on the L side), and unfortunately fuselage wiring will have to be custom because I've now departed too far from the Vans plans.