I have pencil and paper in hand and I am going to sketch out my pack I am wanting to build. What is the standard liter size of a g4 style pack ? I am going to make my pack out of old tent material I have and I am hoping it will be enough. I was going to design it around the g4 shape but now that I keep looking at pics of packs on line, the simple shape of a stanadard z pack zero looks a bit easier for me to make with my lack of sewing skills. Of course I know that this first pack I build will there will be a larger learning curve and I will have more to learn as I go on. To me, some of the z packs just look like a standard large stuff sack with straps and a closure and a wider bottom and I will make side panels so I can make holders for water bottles> the plans on the g4 page I found on line.