I don't really have one baseline setup that I would use when starting setup work for a new track. In N2003 I have a pretty good idea what to use for tyre pressure, camber and a few other settings. Usually I just use a Bob Stanley 'expert' setup or one of my own from a similar track and start tweaking from there.
As for GPL, well, I haven't played it for over a year so my memory is fading.

But you can at least get the tyre pressure and camber pretty close depending on whether the track runs clockwise or anti-clockwise. If it's clockwise (more right-handers) then you need a bit less tyre pressure on the left side tyres and less camber on the right side. The gearing you'll get right just by doing some laps. Well, I can't really remember more, need to check my GPL setups again. Maybe someone else who still plays GPL can tell more.
