I've done codeine a few times and oxy a few times. The euphoria from codeine is mild. After dosing a few times over a short amount of time I found that its euphoric and "nodding" effect had all but gone. Very weak stuff. I have no opiate tolerance. Also, the nausea I got from it was nasty, whereas oxy didn't make me nauseous at all. That said, I still find it provides more euphoria than any benzo I've tried, and of course, it's more euphoric than pot. (Weed is in no way euphoric to me.)
Oh, as for the starting dose, try 60mg to ensure you have a nasty histamine reaction. If there is no adverse reaction, try 180mg as a starting dose. (Don't worry about the 3 grams of APAP. If it's a one-off event and assuming your liver is of normal health, 3 grams of it won't send you to a ER.)