I never said it was unsafe. I've been doing electrical work since I was in trade school, 36 years ago. I simply said I "prefer" to run one wire all the way to the source or load. The wire I run today might not be available to me when I decide to add the circuit 3 years from now. I hate changing colors or style mid circuit. A/C circuits use Black White Red and Green, or bare copper. And the wire is pretty standard. Automotive stranded wire has thousands of variations. This would NEVER work for me, because I might decide I want to use a load that requires heavier gauge, or the switch circuit might need a double pole double throw, or I may combine two circuits or divide one at some point. As I said in the first response, I prefer to switch the negative side of the relay and use 18 or 20 G for the switch circuits like the OEM's do. Again, just a preference.
It might work fine for you, or others, just not for me. And it looks like you are doing a great job I might add. I don't doubt your harness will turn out great. For what it's worth, 20 years ago I'd have had no problem with that style. I'm not against it completely, it's just not what I would prefer.
. Appreciate your input. 
