@hendrikepinpinga,
Well, I did not touch the cron code generating the sitemaps. They still get generated about 5 minutes after any update or new post. Pinging is 24 hours later, giving me time to do any changes I want within 24 hours.
As for pinging, I think it's still the original concept of pinging the search engines all at the same time.
But thanks for the code, it's something I could use :)