Ah, yeah that is the tricky part. You have to find that median. If you stay awake too long, you will lay there for hours. If you don't stay awake long enough, you will lose consciousness. I always like to lean more toward the tired side. I hate laying awake for long periods of time with nothing happening. Make sure that once you have woken up...you remember that you dreamed. If you wake up and haven't dreamed yet, your REM cycles haven't started yet and it will be much like WILDing before sleep (difficult). If this happens, set your alarm for an hour later and perform the WILD attempt then. Remember, you want to fall asleep rather quickly...the goal is just to keep conscious during the process. Just keep practicing and experimenting with how long you stay awake during your WBTB. You will soon find that perfect time that best suits you.