Today was race day, and things went off without too many bugs. The only real problem was the starting switch; it didn't get activated properly on the starting mechanism release. By holding the starting gate where the button is located, this problem was successfully worked around.
The other change that I am going to make for next time is the timer resolution. This time I had 4 digits with 10ms resolution (99.99 seconds max). Next time I will have 1ms resolution, with a max time of 9.999 seconds.
All in all, the race was fun and the kids (and their parents) enjoyed it.