IJC,
So, do you have a talent and/or affinity for drawing or painting? I've wondered whether people who are drawn to a certain type of art might not experience a stronger than normal subconscious connection. To me, music is something I find it hard to live without, and I've been playing music most of my life, and although I do experience CEVs on cannabis, the music is the strongest one.
Actually, I used to experience CEVs all the time years ago, but I rarely do anymore... I remember regularly seeing images that I eventually figured out were from dreams from when I was VERY young (6-years-old and younger, I'd guess). Amazing feeling revisiting a pretty intense dream that I hadn't thought about in 20-30 years... it's like your brain never really forgets it, and once you manage to "find" it, it's as intense as the original experience.
My CEVs were always very fleeting, though... like stills flashing in front of me, several times a second... I got kinda good at latching onto one if I wanted to, but at the expense of falling off the train I was just riding.
It sounds like you have longer-lasting and much more intense visuals, though... especially if it's with your eyes open. Very cool.