True coobies, the grounds would only have to be 12 to 18 inches and the all you need to worry about would be 3 to 4 feet is 1/0 to up the alternator wire. Search 0 gauge or 1/0 on ebay. It's not that much money.


Wire

http://www.ebay.com/itm/0-Gauge-Wire...3D162172483020


connectors

http://www.ebay.com/itm/Earthquake-S...kAAOSwA3dYhmAC


heat shrink

http://www.ebay.com/itm/1-1-4-ID-1-2...ar=&hash=item0

This is just an example of what you can find cheap if you look. You can find it cheap and save money and your truck..lol
The color of wire is not that big of a deal if you use the heat shrink and a little paint if you want. Truth be told, I think you got charged a lot of money given the fact that you ran pretty much all the wire and installed the speakers. Just looking out. That cheesy ground in pic 1 you posted is in my opinion unacceptable and if it were my shop your truck would not of left the shop with it like that.... Just saying.

 

You can also check out local welding supply stores for 1/0 they usually have high quality wire for great prices. The wire will be more rigid however, but I'd choose that over flexible out in the engine bay and under the body.