I fitted a new clutch cable recently and tried a few different routings. The best route for me, with Euro Interstate bars, was along the front of the oil tank, in front of the battery tray, over to the left side of the bike, outside the left (primary side) downtube and then underneath the main spine in as straight a line as possible. I have a Taylor type head steady, and I'm not sure if the standard head steady would get in the way. I tried routing it through the grommet and it definitely wasn't the best. Any other route on my bike and the cable was too long to have a nice smooth arc both on the bend around the steering head and where it curves down to the gearbox. It may be different with your bike, though, so you could experiment a bit till you find the easiest pull with the fuel tank in position.