I've been working on writing documentation here:
http://wiki.nesdev.com/w/index.php/Vs._System
http://wiki.nesdev.com/w/index.php/INES_Mapper_099

We've recently had a few questions come up regarding timing, and I was wondering if anyone here either knew or was willing to measure:
* How much time it takes a coin to fall through the coin acceptor (and how long does the switch read back as true) ?
* At minimum, how long must the game drive the coin counter's electromagnet?
* Can one damage the coin counter by leaving the electromagnet on?
* How reliable is the timing on the watchdog circuit (that's reset by reading from $4017)?