5x6 is my preferred size for me and 1 kid. I have long legs and hate a box that is only 4' deep, I can't turn in my chair without my knees hitting the wall studs. I have a 6x6 that is also pretty convenient, in that it allows me to scoot to the back wall and stay out of my sons way. I also am able to bring my laptop and get work done in this one while we are getting a hunt in. I just finished a 7x9 that will be in my largest field and should allow me to take all 3 kids when the need arises.

I build all of mine out of whatever material I have readily available. Some are all tin (loud and hot, but will never rot), I have some that are painted plywood and are already starting to show signs of needing attention. I have a couple that are painted OSB they seem to last about the same as the plywood (10 years or so, then start to need attention). My 7'x9' is cedar floored and some of the frame, the walls studs are rough cut heart pine with vinyl siding covering the outside. I prefer plexiglass windows that slide open, shelves in the corners for binos, cups, etc.., carpet on the floor, and a carpeted wide (8-10") shooting shelf at least along the primary shooting window. I have started cutting a V notch in the corner shelves to help hold a rifle barrel so it doesn't fall if bumped. Also I want a door I can walk through, leaning over some is fine, but I do not want to have to crawl in on my hands and knees.