How many meters of tubing would I need ?

probably well under 1.5, are you getting the rasa kit? it's supposed to come with 2 meters, but unless you are mounting the rad outside of the case you might not even use a meter if you measure twice/three times before you cut, but since people make mistakes it's best to get a bit extra

So 2 meters is ok ?

I had ordered five metres of tubing for a new loop (reservoir -> pump -> radiator -> CPU -> graphics card -> reservoir) in a Cooler Master HAF 932 case (pretty big). Overall, I don't think I even used half of that length, so yeah, two metres will do!