I am with Buff and sometimes place "extra" in areas that produce fish .
but I also drop on the edges of channels and...
sometimes in sheltered areas just to run from whatever might make my experience unpleasant
as far as what depth ,that is where it gets tricky as every lake seems to be different on average depth and where the fish like to hang .
also some of it depends on time of year you want to hit said cover .
shallow stuff in the spring , midrange summer ,deeper stuff in the winter
my 2 cents and to be sure a night run is suggested for the actual placement time
and don't sit on it every time you go to the lake
otherwise the world will be on your spot quickly ,just saying