TOTD - you clearly didn't read the last line from my last post then.
I have colleagues who have experience with UAVs using cutting edge technology and the scenario I mentioned is the most likely way to improve search efficiency.
Don't try to replace or replicate the helicopter search protocols with UAVs, use them for what they do best - large area, high altitude scanning with multiple sensors.
You don't have to tell me about search and fatigue - a 4-hour search of Swansea Bay on NVD in a 200' cloudbase and p8ssing rain was one of the most tiring ones I have done - but a UAV would have been of no help in those conditions.