Also I've just discovered the work of Jurge Ziewe; He fell under my radar but he's been performing OOBE's for decades but his experiences with it came about incidentally through his 4-5 hours of meditation a day. He reminded me of you, Jhanananda, when I read parts of his biography and a couple of his books. He might be the only publisher in the field of OOBE literature who talks about it through the lens of meditation. He mentions he never tries to reach it but simply lets go in his sessions and it happens to him, especially while asleep, like you.
I wonder now about many of the OOBE writers. Many of their techniques involve some form of hypnotic trance induction that could be likened to meditation but I can't imagine it working unless one spent hours which would amount to meditating at that point. Then again, there may be some people who are just naturally talented and can leave their body naturally like Robert monroe and others. I enjoyed monroe's tapes but until I began meditating, I didn't really have much success. Same with robert bruces publications, though he does have meditation exercises listed in his books.