im still playing with my down rigger setup.
i use a 3lb cannon ball and it stays pretty much straight down at walking speed trolling at 80ft or so. easy to track on the sonar
cannon ball weights are much cheaper than the finned down rigger weights.
i did pick up some two pound weights at the sd anglers swap meet. 3-2lb cannon balls for $5.00 couldnt pass it up. i havent used them yet. i hope dont need to.
i also use the stock scotty release. seems work well.