Russ - If you think sexing bgill is risky wait till you try sexing LMbass especially out of breeding season.
When I chose male bgill for my restocking they first go into a rearing cage for at least one summer. Sometimes some remain in the cage for as long as two summers. This wait period allows for additional development of sexual characters. Releasing "all male" bgill prematurely into your pond often produces results such as presence of bgill fry (Cecil's recent experience). If you reread Cecil's post, he mentioned that due to special conditions the fish were prematurely added to the pond from the holding cage and the "wait time" did not go the proper period. Cecil was also dealing with several hundred bgill, all at one time, which when under pressure and in a hurry can contribute to errors. I never trust someone else's sorting; I always double check my fish if it is an important project.
C.Catfish when sexually mature (larger than 20") very often "work the sediments" and disturb bottom materials during spawing activities. Some people consider 2-3 ft of water visibility as clear water.
