its not so much that i want to maintain contact with the bottom throughout the trolling, but moreso i want to be able to stay clear of the bottom when i inevitably start running into it. i figured the bottom bouncer would be better at not snagging up when im in shallow and would run decently in open water. the keel would run more nicely in open water, but not as nicely in the rocks. without having a graph to know what im coming against, i figured the bottom bouncer is a safer bet to keep the softer mono/fluoro clear of the rocks because of the wire. the keel would run it much closer to the rocks and be more susceptible to getting pinched between rocks and breaking off.  

i would be using this application at dusk/dawn to target the bigger female walleyes. during the day id be in more open water going after lakers for lunch.