yeah, as far as spacing etc etc, i have never built a vert yet, so just follow the journals.
one thing i can help you with. . . get a bigger pump. thats a lot of hose you have to fill, and you are gonna have a lot of lift to get it up to the top. . . i would suggest something 750-1000gph, that should give you 8-9 feet of lift, to get it to the top and still have power to distribute the water evenly. gonna cost you 50-60 bucks.
i think 25-30 gal would be a good size res.