Peyote will generally last about 8-10 hours of prominent effects, 2 hours of returnin to baseline, and after effects of anythin up to 12 hours. Dosage depends on the size of the cactus and of course the potency, so u mite want to test it. 3cm diameter peyote, you will need around 8-10 for a trip that will last what I described at the beginning of the post. For bigger ones like 5-6cm diameter heads, you'll need 3-5, 6 if ure stomach can take it. Some ppl hav problems with nausea and others don't, oh and if uve ever seen fear and loathin in las vegas, you will know the notoriety of waiting for this to come on, took me 3 hours, and within 15 minutes I was literally on my back, gr8 trip, ultimate bliss, incredibly detailed visuals, mad auditory modifications.
Have a good trip