Micro OBE's - using a timer to LD/OBE

[infinity101]

I need help, i know how to set the timer im using a flash timer from How To Trick Your Body Into Falling Asleep To Have Your First OBEs And Lucid Dreams In The Minimum Amount Of Time (which is a very good website for LD/OBE tips btw. So plan is to wake up at 5am, stay up for 45 minutes then go back to sleep, do i set the timer on straight away? or should i set it to start in 20-30 minutes?