I'm building my own pull-behind sprayer, partly for budget reasons, partly for the fun of it. I need some help in selecting parts for: - The flexible tubing for the boom, (planning on having it 6 feet long) what would I use? - The spray tips. I'm not sure where to get the right ones, how to space them, how they should be priced, etc. Also how would they tap into the tubing? - Pressurization stuff. I'm planning on having it operated by being placed under pressure before-hand, kinda like an aerosol can. I'd like to have the stem like you put on a tire put on it, so all I need to do is to get the air tank out and put some air to it. - The valve. I'd like to have something that I could turn on and off from the mower. Any ideas?