i would say that it varies depending on the dose but for me it lasted give or take 6 hours, less when smoked. i'm not sure of the effects or even the duration yet. when i get the chance to experience more i will update you guys with a more serious and more lucidly articulated experience.

also i'm not sure exactly whether or not it's easy to contact people within the dream world. i hear silene capensis is better for contacting someone. but from what i know it's possible with ordinary lucid dreaming practices.