Fogg dam's definately a good place to go at night, however not advisable to be walking along the waters' edge as there's a 4m saltie cruising around in there. It is possible to spotlight crocs from the car as you drive down the road, and last time I was there we found 3 water pythons all over 1.5m just sitting on the road. However, as someone previously mentioned it is illegal to "interfere" with reptiles in the Northern Territory without the appropriate permit. Unfortunately this does include handling and moving even if it is for photographic reasons. Who was instructing you on the "hook and tail technique?"