Where are y'all coming through the firewall at? I couldn't find any grommets on the passenger to come through.
Just run it under all the way back and put a hole in the backseat. It's much easier. My hole is just beside the seat brackets on the left side.
I've put my truck in a LOT of places it really shouldn't have been and had no problems with power wire and install looks good to me IMO. And I don't have to deal with poorly fitting trim because of the wire bulge
hence why i said smaller than 1/0 can go under the sill. you wont have bulge if you know how to fit it in there and take the sill on/off