How can I track my REM cycles?

So I've been working on this technique, basically a tweaked WILD I guess, but it's hard to know when I should wake myself up to try it.

The first time I pulled it off I had woken up on my own and it was super easy to do, like I was in a dream within seconds which is not normal for me because I usually find it really hard to fall asleep. The second day I tried it I had to set an alarm, and I think because I wasn't synced up with my REM right, it was a lot harder.

It did actually work again, but it took about three hours of laying there, and by the time I was getting in and out of dreams it was time to get out of bed.

Just setting an alarm for 4 to 6 hours after I fall asleep seems so crude and ineffective, is there any good way to track my REM cycles so I can time doing this better? Or should I just only bother trying on days when I happen to wake up naturally with a few hours before my alarm?

One thing I see suggested is to jot down the time when you wake up in the night, because waking up I guess after a REM cycle is normal, but I'm iffy on trying that one. For one thing I never remember those short wake ups, maybe there's a way to work on that, but even if I did, I feel like turning on the light and writing something would wake me up way too much and make it hard to get back to sleep.