Cant remember ever using a rear anchor while up sturgeon fishing. May have thrown a drift sock a time or 2 to help hold the boat in position. Think we had one year with 20 to 30 mph winds out of the NW that I just left the main motor in reverse all day.
For a rear anchor I would think something with a lot of weight would work best. Isnt that anchor usually on a short rope pretty much right under the rear of the boat?