Reading back the OP and the replies, I realize that I failed to mention how I am particularly fond of repeatedly smoalking bits of changa, spaced apart by 20 - 30 minutes.  Because of the harmalas, only tiny successive hits are needed to keep the tapestry afloat at the desired velocity and altitude. 

It is an entirely different experience to be gently floating a longer time, compared to being shot out of a cannon when vaping straight freebase.