This is generic "turning" advice for anybody planning to fly near or below the recommended weight range of any weight-shift hang glider. This is not to say that I recommend that choice, but this is as much help as I can give on turning, whether the pilot is light on the glider, or maybe the air just wants to put up a fight, one day. This technique can also help anybody flying when big air gets under one wing, but beware, the air can still overpower your best efforts, at times.
The trick is to initiate a turn with a sudden yaw, not just a bank. Right turn: With arms held at the normal cruising position, hold the left arm rigid, and pull the right corner of the control bar rearward, hard and fast. Your feet will swing out toward the right side wire, and you want to keep them there. Bring the rest of your weight to the right, then. Fly the turn normally, keeping the feet to the right. The left turn is the same process, holding the right arm rigid, but with everything going to the left side instead. If you are doing this turn to enter lift, keep the bar pulled in, as the nose tries to surge upward, entering the lift.
There are reasons why this "yaw" technique works. You out-mass the glider about three-to-one, so the hard and rapid twist of your body under the glider causes the glider to yaw toward the "feet" side in reaction. The glider enters a slight dive momentarily, dumping some of the unwanted lift, because you are also moving your weight forward a bit. Extra speed means extra control authority for the pilot, too. If the yaw is strong and fast enough, you can actually pull the inside wingtip rearward, which helps greatly when a wingtip is being lifted. The glider turns and enters that lift more nose-first, rather than getting dumped out in the opposite direction.
Now if you are light on the glider, chances are that you will need all available forward speed more often than the heavier pilots. Wind speeds may increase as altitude increases, or you may find a Venturi effect happening at the ends of a ridge, or when crossing a small valley in a ridge. Again, this "fast" technique applies to all HG pilots who need to:
* travel very fast for extended times,
* at a low drag profile,
* with fairly easy effort,
* turn slightly with precise control while at speed,
* fly with the basetube well to the rear, beyond the reach of their arms.
Everything described here will need some practice, to nail down the technique, before you really need it. You will need some body-experience to get things right, not just head-knowledge.