That was more than a decade ago, but I believe the highest I went for was about 4-500ug (according to the vendor, it was on a postal stamp so there can be quite some variance). I was exploring psychedelics several months in a row while increasing the dose, so there might have been some tolerance buildup. And it wasn't that I had no visuals at all - juar there was nothing visually profound, just some things shifting and moving here and there, people outside looking a bit strange, etc. Felt more like strange, weird drunkenness than anything. It was not at at all an uninteresting experience - just extremely cerebral. I tried DMT several times by the way, but couldn't break through - it gets very scary very fast, and the taste is like smoking a plastic bag, which was in itself quite off-putting.

Depends on the coffee intake and stress; when I am on vacation, I sleep 7-8 hours without waking up. I am lucky that I don't need to pee during the night, though.