Adam - Just unscrew the lower shock eyelet about 2 turns from the top of the thread, this should give you enough shock length to have a massive amount of droop.
Also gents i have found that on shitty unprepared tracks if you run an excessive amount of droop the car can actually be much much smoother to drive, the tracks we have in Australia tend to have very little traction and be very dirty, so limiting the droop too much can tend to make the car react unpredicatably.