How is this possible with 6 hours max sleep per night?

New here. Lucid dreaming seems pretty cool if I can pull it off without it running my life. Going back to bed for an hour or two after sleeping for 6-8 is impossible when you run your own business.

Is it possible to do a WBTB or even DILD while sleeping only for 6 hours? I figured out my REM cycle, it's 2.5 hours (yes, I have awaken from dreams at 2.5 hours and remember them vividly), 4 hours, 5.5 hours, 7 hours, etc. My question with this is, if I awake from 4 hours of sleep (at the end of my REM cycle) and I stay up for 90 minutes, will I re-enter in REM, or do I have to go back to bed for another 90 minutes? What confuses me is how sleep cycles work after you wake up; ie. if I'm awake for 10 minutes or 60 minutes or even 113 minutes, in which case is REM a greater chance to enter? (60 would be just under 90 but 113 over.)

If I could enter lucid dreams while in a dream that would be ideal. I find that doing reality checks during the day somewhat retarded, as my entire day is focusing around doing reality checks every half hour, when I should be concentrating on working. Is there any way to know you're in a dream without having to train yourself with reality checks every minute of every day?

When I was a kid I was able to lucid at will. It spawned from nightmares and when I found out I could enter/exit dreams at will, I took advantage of it and became god. I want that back. It just seems that now I'm unable to do that.

I've also tried auto-suggestion, but it's hard because I can't wild when first going to bed, and keeping that in my mind for hours is a little difficult.

Any ideas would be great. Thank you all for your help. I want this so bad.

Frank

Reality checks dont have to be that hard just everytime you think about it ask if your dreaming plug your noes and try and breath and go on with your day.

WBTB might be tricky on only 6 hours of sleep, only because, I don't know about you but at that point I'd be concerned with getting as much sleep as possible :P
DILD should be ok, though, as long as you are remembering dreams you can DILD. Also auto-suggestion/MILD has, in my experience, actually worked best when the intention was set when I went to bed, then just kept in mind as I fall asleep. MILD worked fairly well for me at a time when I was doing few waking reality checks. A better way to practice RC's, however, s to just remember to do them whenever you see or feel something strange or when something seems out of place, even though you're awake - numerous times I've done a RC thinking "ok I know I'm awake but I'll do it anyway" as most do in waking life only to find that I was infact dreaming.