just one line would be all you need....it is big enough to lift the line weight all the time..
i would use 250~300# (140 DaN) all the time on it...you could just go up to 500# (~220DaN) line and call it done in case you end up in high winds you would not need worry about the line breaking....just the frame instead

it will be a great lifter too...
4m kite...nice one...