Don’t get too hung up about trying to get the rear wheel lined up perfectly with the car centreline using the laser method. When my belt is running true the rear wheel is pointing somewhat to the right, as was another I’ve checked.
The main thing is to get the belt running straight when going forwards, and if that means it’s sat 1/4 inch off the outside of the rear sprocket, so be it
When reversing my belt creeps towards the inside of the rear sprocket, but that’s OK as I don’t do much reversing.
What you don’t want is the belt too close to the tyre. You may see signs of it catching the tyre in the form of a pattern on the tyre wall, even if it there is a reasonable gap when parked up. With my belt set up I’m able to run a Yokohama 185/55 AD08R on the rear.