wow 8 hours is a lot of time to have an active effect!
I have never tried any type of hallucinogen although I have always been curious about what type of things would I see after using them. Still, since I don't enjoy messing with my brain I have remained firm with my decision of avoiding all of this stuff.
Yes, 8 hours so imagine everything that could go through the mind of a person at that time. Being out of control of your mind is something that generates a lot of concern. As you say I prefer to have my mind fresh and without subjecting it to strange things.
More like 4 or 5 hours, depending on the dose. Take multiple doses through the night and next day (for example) and why let the good times end? But that's multiple doses. Just make sure you've enough things to keep you entertained. Music / art / other people / a lover ;) ;) ;) (I lie about the last bit, you really wouldn't be able to do much whilst peaking and even when coming down it can be more than a little weird).