Heh heh....Hi Alfisti!
Yeah, I've used a lot of 845 and yeah it does layer for me. I always wait a day or so between applications but I have no idea whether that's really necessary and I suspect that it's *not* given the product's original application/purpose.
No issues with pseudo-holograms (that was with FK1000P under certain circumstances) or with QD-sensitivity (that was with 476S).
BUT...appearance diffs between 845 and 476S seem to fade/even out after a wash or three and 476S is far more durable for me (if less trim-friendly). And FK1000P is *FAR* more durable then either; I switched most of my drivers over from Collinite even when it looked better (to me) because the durability/protection of the FK is the best thing I've tried this side of a coating.
These days I really only use 845 as the base layer under 476S. I do this because the 845 *is* much more trim-friendly and it's a lighter product less likely to cause issues over a seriously imperfect paintjob (think pits/not-so-micro fissures/etc.) and I only use Collinite on paints in very poor condition. When I used Collinite on other vehicles, the 845 base layer helped with the issue of product build-up along PPF edges (and remember that I apply *VERY* thin layers...still sometimes had problems but the 845 helped a lot).