I usually pump my HIFI Comp up until it only just creases slightly in the centre of the LE when ya hold it with one wing tip on the ground and put pressure on the other side of the LE. (i.e. put downward pressure on the LE to fold the kite in half).

The 08 HIFI's have a few different attachment points on the 5th line, from memory approx 30mm apart. i always ride them on the 5th line knott furthest from the kite.
Im interested in how the 09 hifi comp would fly with adjustments on the 5th line..mmm..

Though just remember if ya shorten the 5th line too much, youll lose its power coz it'll be flying only on the front 5th line, with minimal backline tension.