The 747 is very challenging to 180 on a 150' wide runway. I prefer to turn left to keep myself on the inside of the turn. However, I have known visual reference points on the windscreen frame to help judge when the right wing gear is approaching the edge of the pavement before initiating the left 180.
When first learning to taxi the airplane, I had the other pilot actually go out on the ramp one day and walk straight ahead from the wing gear so as to calibrate my eyes to some handy visual references from the inside structure of the cockpit.