RCA Cable Length & Stock Speaker Wire Gage

Hey guys, I'm trying to finish up my audio build and had a couple questions. What length RCA cables are you running to behind the rear seats in a 3rd gen double cab (down the middle/around the sides)? Also what size are the stock speaker wires? I'll be sending 75 watts RMS to each speaker, is 16 gage enough? I tried looking in other threads but couldn't find a definitive answer. Thanks!

 

Maybe this will help. Not sure if what you’re looking for. I think you divide 75 watts by 12v to figure size in your case and then how many feet you’re running or the wire. I screenshot this from a question I had from lighting section of board. Sorry I know it’s kinda blurry for some reason. I think by chart you would be right between 16 and 14 gauge needed so probably be fine but I’m not expert

 

Thanks!