Hmmm.. suppose i kind of did but for it to work properly i reckon a average score should be taken from say 4/5 weeks for each driver therefore giving them their individual grade with the top grade being 100, this could allow for people to improve there grades or drop grades etc. etc. Meaning everyone would be in there correct heat racing with the right speed people if that makes sense. It also means you have to work for your grade.
For one off drivers such as Kev im sure a little common sense can be used

. But dont forget as Mr. Andrews says someone has to find the time to sit down and work out these grades