I detect even down to 5-7ug LSD that I'm dosed (though I'm quite experienced with all kinds of dosages).
75ug is definitely tripping-level. No way someone couldn't detect that they are dosed, just the contrast/visual-enhancing qualities alone should be enough to detect that, maybe even some LSD-typical distortions can occur at that dose...
It's unfortunately not really legal though where I'm living.
AFAIK there are a few psychiatrists/researchers around the world where it's approved for clinical studies, where you could try it in a clinical setting. But unfortunately you're often still on your own with trying it. I tried microdosing it for treating ADHD, but I'm not really sure if it really helped there, and I'm back on the usual medications, YMMV though, as LSD has mild stimulant properties as well.
I may try a combination/mix of LSD and other ADHD medications in the near future though.
It being a neuroplasticity enhancer doesn't necessarily mean that it's enhancing in a good/healthy way. I noticed that my thoughts/imagination have gone a bit more "visual" (not sure if that's really the right term), I'm not sure if it really made me more creative. I think for me it mostly manifested my mind further and I'm a bit more in tune with nature etc. (much more conscious of all the "ecocrimes" humanity is doing).
This may not always be a good thing if e.g. you're prone to conspiracy theories. It can also mean that it's promoting growth in areas in the brain that shouldn't be connected (e.g. leading to psychosis), it's still a powerful substance which should be handled carefully.
But in general I think it still takes some time until this is a clinically approved substance. I think it will likely be for stuff like depression or PTSD or generally disorders originating mostly in the frontal lobe. I have certainly noticed the antidepressive properties of it (although I never had a real depression while taking it).
But I'm quite hypersensitive to substances in general I think, so my experience may not be representative.