You don't really need to remember them. When you are used to, your fingers will move "by themselves". It is something often referred to as "muscle memory" in here. And you have access to more keybinds than with the numeric pad.

Question about T6: just tried yesterday, even if we manage to kill the central bulb quickly enough, I feel like not dpsing as much as I can. The fact is that I am not sure about my position as the bulb is right at the same place as Rafflesia. How do you see your position with respect to the central bulb?