We had a total of 91 cars registered, spread out over 3 divisions (Open, Sparks (grades K-2), and Clubbers (grades 3-6). I used the chart-generator on Stan Pope's website ( http://members.aol.com/standcmr/ppngen.html ) to generate reference charts for from 5-to-60 cars, realizing that we didn't know how many racers would actually show up. We have 2 four-lane tracks, so I created all the charts for 4-lane tracks.
We ended up with divisions of 7 (Open), 43 (Sparks), and 25 (Clubbers). I used my spreadsheets to assign each car a registration number, which was bounced against the car numbers in race chart matrix to create actual race charts using the kids' names and unique car numbers (which were assigned when they bought their kits). In a matter of minutes we had printed out complete racing charts for the precise number of cars that showed up.
For our two larger divisions, we ran 1 "qualifying" round for each (25 and 43 heats, respectively), then took the top 9 cars for each and ran a "championship" round to determine first through third place. I'd hoped we could run our championship round as 7-3 perfect round-robin, but we ended up with 9 cars tied for the first four places in one division, and 9 cars tied for the first three places in the other. As it worked out, I think we made the right call to go with 9. We had no complaints. In fact, we had many compliments, and everyone stayed until the end.
Registration lasted for an hour. At 7:00 PM we had our introduction and Gospel message, while I busily printed out the racing charts. Racing commenced at 7:20. We were completely finished by 9:00 PM.
Below is a link to a page with links to copies of my "results" spreadsheets. I've removed the kids' names, and just used Car Numbers, for obvious reasons. If you study the Clubbers' charts, you'll notice some interesting developments, especially as it relates to the first- and second-place finishers.
My 3-year-old daugther's car won the Open Division going away, while my 8-year-old son's car was third in the Clubber's Division. No, we did not race them head-to-head.