I think a patent and participating with the likes of Bass Pro or Cabelas would be a better move. Details can be hammered out, or negotiated as indicated. Since you have already invented and have product in stock, and not seeking help to get proto type assembled or produced, but to distribute and market a ready made product, I think and Invention show is more of a circus attraction (gawkers) than a marketing tool for individuals such as yourself.

If it was a Fishing Expo, it would be another thing and probably not as expensive. In a Fishing Expo you can do some networking with other marketers and retailers in a related industry, and as a bonus have other fisherman do promotional and PR related stuff at no cost. An example would be a product called the "Pole Cat", that was first featured here (Seattle) at an Expo years ago by the inventor, and it is still going strong today. It can now be found in a number of local Tackle shops and has found tremendous popularity over the years.

Another ideas would be to get "BUZZ Ramsey" to partner with, and offer his name, for the marketing to Steelhead and Salmon fishers. lol

Good luck, and I look forward to trying one, as I do love to bobber fish. I wonder if a stiff current would aid this bobber for better presentation while fishing for Steelhead and Salmon. It will be hard to beat the Dink float but we'll see.