excellent idea of multiple sections. In your example the sections would take 19 rounds at most, the final of only 13 people would take only 12 rounds.
I would suggest you keep your totals throughout the tournament as well.
In the hypothetical version where you get only 30 points, is there still a 500 point bonus? Or would it always be 1/40 of the starting total? Or would it depend on the number of players?