This. When I rebuilt my car with new everything, I had to start from scratch, so I took the time to measure it out with string. I then out of curiosity took it to Abbott Racing to get it checked (mainly wanted to be nosy and used it as an excuse to go there) - was bang on the centre of the required spec.
Thanks, that's good to hear. My garage is nice and flat - well from as much as you can tell from using a spirit level - it's one of the first things I checked.