Can anyone try this ?

could any confirmed lder try using a sand clock to try to see how long thier dream last ?

Can you elaborate on that a little more? How long as in "dream time" or real time? I can tell you that REM stages get progressively longer during the sleep cycle. They start out at about 10 minutes, then stretch out to about an hour after a few cycles.

How would someone time only the REM cycle, and why does it need to be on a sand clock?

Count seconds instead. Make sure you count all of them and don't skip anything.

I mean to time your stay in the dream like knowing how long it will last in the relative dreamtime since a chronometer wouldnt work cause time has no sense in a dream

Unlikely, a better bet would be to video tape yourself. Give the cam a signal when you are falling asleep, give it another when you wake up from the dream.

Define "sand cloak". I am not sure what you mean there.

Guys i mean like in waking life if they tell you to stay in the mall for an hour u would have a chrono set for an hour but in the dream u would have a "clock" to know how relatively the dream time will last