So - if you have already loosened the toggles under the cockpit rim and are not getting the height you want, untie the knot on one side and thread it back though till you can get rid of the downward pull section. That would be where the bungie is connected to something closer to the hull than to the cockpit rim.
Now reconnect it all (take photos before you unthread so you'll be sure how to rethread - or just look at the other side) and it SHOULD pull upwards to the cockpit rim level rather than half way between cockpit rim and hull.
Hope this helps!!