Diving weights for trolling

Now that I have a bigger boat I want to start trolling some deeper water, but I can't spend much on equipment. Has anyone experimented with diving in-line weights? Or tried these Tadpole weights?

In-Fisherman did an article on them I believe in this years Walleye guide that they put out at the beginning of each year. Otherwise you might be able to email them and ask them when they published the article.