When To Wake Up?

So I read on the main site that the best way to remember your dreams is to wake up during or slightly after the REM stage. The site specifically mentioned waking up 4.5, 6, or 7.5 hours after you go to sleep. Using this information, I've tried setting my alarm to wake me up 9 hours after I go to sleep, thinking that will be near the end of the cycle, plus if I sleep a long time the REM portions of my cycles will be really large near the end and I'll have a better chance of waking up during a dream. Unfortunately I'm having a hard time waking up during a dream after these 9 hour periods. I am managing to remember my dreams, but they are pretty vague.

So my question to you is, based on your experiences, what is the best length of sleep to ensure dream recall?

I've always found that waking up naturally allows me to remember the most dreams, and that's after about 9 hours!