First off: Next time when making a thread, please try to write it in more coherent English with proper punctuation. It's very annoying to read and to understand what you mean by what you're writing. Also, there is no need for capslock. I'll leave this thread be but if there is another one from you like this I will instantly close it. Hope you understand.
They are about equipotent.. IIRC (don't quote me on this though) 1mg oxycodone IV = 1,5mg morphine IV. Why don't you just google an opioid conversion chart?
Looked it up for you. A chart I found says that 2.5mg morphine iV = 1.66mg oxy IV.
Rectal oxy isn't worth it as the oral BA is more than 80%. The onset might be faster, but there isn't even a real 'rush' from IV oxy IME, so I wouldn't count on a rush from plugging it. If you want it to kick in faster it might be worth it I guess, but that would probably lessen the total duration of the effects, which wouldn't be worth it for me.
Rectal morphine is around 40-60% which is twice as much as oral (20-30% ), so that would be worth it.
IV/IM is, obviously, always 100% BA.
Hope that answers part of your question.