TBH you're opening a whole new can of worms when you start adding corner numbers, as many people define them differently - for example the chicane can't just be called turn 2, as it blatantly isn't just one turn...
I just count chicanes as one corner - and it's also just for official purposes. Just call it "chicane" Instead of turn 2 or 2/3/4 or whatever. One problem could be the SO double chicane...
I don't think that reverse turns/splits are that necessary, as they stay the same. But I'm thinking about it.
IMO the picture is a bit overloaded now, just leave the numbers for the standard direction and we'll just have to use a bit of logic to figure out the numbers for reverse.
On second thought, it will look overloaded only on small tracks, on Westhill for example it should look good and professional.
I just made the SO configs and will upload them now. Unfortunately the trackmap template is a bit confusing so there is an ew one which supports resizing images. http://en.lfsmanual.net/wiki/Tracks:South_City
Would it make sense to edit the car groups on German LFS manual a bit and put the MRT to the Formulas (to become a S-S group), the UF1 to the XFG and XRG (STD cars), the LX4 to the LRFs and merge the two GTR classes?