We don't do cultivation questions. There are websites that do however if you take time to Google.
The comedown is more of an afterglow than a real comedown (in a stimulant comedown sense).
Will I crave after my first dose? And how much should I have if I eat it my first time?Opium will definitely lift your mood, however after consistent dosing opiates tend to cause worsening depression (re: apathy). Of course there is a high probability of physical dependence should you choose to use on consecutive days. Opium is no joke, it's not like weed where you can put it down and not worry about anything but mild psychological cravings. Be careful.
Ok thanksIf you have good quality and dose it properly you'll likely not soon forget the waves of euphoria, but you won't be addicted after a single use. I can't answer the second part of your question accurately not knowing the quality of your opium or opiate tolerance. Generally you'd start with an amount slightly smaller than a regular-sized marble.