Completion of corrective structure, 600 pips down in GBPUSD

HI All,
we are currently completing an impulsive movement up, which seems to be wave C of a flat corrective structure, which in its turn is just wave B of a larger corrective structure. So once the impulse completes in 1-2 days I will be looking to go short in GBPUSD for an opportunity of 500-600 pips.