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Fair warning- the more you outfit (or just put stuff into) your boat (in general), the harder it will be to remove yourself in a worst-case scenario. If you don't know much about knee blocks, and are considering them, then you need to be aware that they can make it MUCH harder to get out of your boat they are put in incorrectly.
In general, buy some minicell foam, sit in your boat, and get creative. The contact cement that Leland Davis recommends is what I've always used, and it works wonders. Read application instructions carefully or it won't work.
Good luck with outfitting. It's a great feeling watching others peel themselves painfully out of their boat while you're sitting in comfort.