you know, the fun part of setting up your kayak is doing it yourself. being a mcgyver type, but sometimes it is okay to go ahead and buy something that someone else has made and put the time and effort into.
i too was looking at doing this whole setup without going to the shop and buying it off the shelf. after experimenting i realized that it would have been cheaper to just buy the item instead.
i have used the mad frogger and it is a nice setup. it allows for you to customize it for your needs and it works well. you won't have to worry about whether it will break off or corrode in the salt water. i do have to say that for what it is it seems expensive, but if you were to purchase your own materials it may come out even.