I've only been trying since last week a total of three times and yeah, I feel symptoms. Like I'll feel dizzy and tingly, but almost in a pleasant way, not how it would typically be.
The second time I even heard the voice of one of my CCs although he's not from the reality I was trying for so the task failed successfully.
Overall I do feel fairly close because it's hard for me to actually do it because I get snapped out too early and open my eyes or I start feeling too tired and I can't keep it going while I'm sleeping because my earbuds are small enough to get lost or god forbid, I accidentally choke on one 😱
I'd definitely also invest in one of those special sleeping headphones like these so you can keep it going all night if you're like me and can't just use a speaker without disturbing others.
And it definitely will happen eventually, just keep at it and remember to take breaks between attempts because it will be physically and mentally draining if you keep trying to shift every night