I can't tell you how much to smoke as all opium is of different quality and strength. I will tell you that I know of many people who tossed off their first opium experience as "eh, it was ok, I got comfortable and relaxed". Well I am here to tell you that you didn't get what you are supposed to get. You will get warm, sublimely wonderful flushes up and down your spine and body. The back of your brain is carressed and that caress extends down to your shoulders and arms. You will be energized and in an enthusiastic but still languid mood. This goes away to be replaced by a "nod". Within that nod you find yourself in a waking dream state that is second to none (in my opinion, K enthusiasts might differ). You can project yourself into those dreams of fantasy and time is slowed to a crawl. If you take enough you will go in and out of sleep over and over again. I have taken amounts that will last me an entire night of dreaming and waking, waking dreams and sleeping dreams that seem upon arrising the following day to have lasted far longer than they did.
First, you must smoke the opium properly, do not apply a flame to it or you will burn off much of the active chemicals of morphine and codine.
Second, titrate properly, you must find that balance between your initial excitation and nausea. Opioids affect your brain, your stomach and your intestines. The stomach will be affected and you can get sick enough to throw up especially during your first few times - if this happens you smoked too much (or you are willing to let the bad effluent out of your body and within moments you are perfectly fine).
Once you do have the effect, then do a mix with your favorite herb but don't smoke them at the same time.
Finally, when you figure out how much you can take, eat it. You lose your initial rush but you gain in duration and depth of your experience.
In my travels I have yet to meet someone who has not been awed by opium when they have smoked it properly.
They don't call morphine GOM (God's own medicine) for nothing. It puts everything else (including heroin, in my opinion) to shame and the mix that is opium is comparable to nothing else.