Drocket,
I wanted to make the daylength 90 minutes.
So I edited the days.cfg file to Length 90 and also the SECONDS_PER_DAY in clock.inc to 129600. (actually, I'm not too sure why you need SECONDS_PER_DAY at all since it appears you could calculate it from days.cfg)
Can you think of any other places that set the length of day?
(.status has the wrong current month times)
Regards,
Stephen Donald.