I have build many Versa wings. Mine are not stock, I've made many modifications. On mine, each wing half is 20 inches long, for a total wing span of 40 inches. The stock wing is slightly narrower, I got tired of cutting off part of the width. The wing cord is about 14 inches in the middle and 5 inches at the tip. You would be well served to start with the stock plans. My Versa's will have an all up weight around 23-25 oz (650-700g), I'm not sure what the maximum weight would be, another 10-15 oz would be possible, lighter is always better.
The pusher Versa is notorious for being difficult to balance. The Versa, as any flying wing, is very sensitive to CG. The most significant modification I have made is to move the motor forward from the stock location (about 4 inches). I did this to achieve a proper CG without building a nose to move my battery forward beyond the stock wing.
Here is how I found where my motor needed to be. Build the wing, without installing any electronics. Then put the plane on a balance stand, then place the compotes where you would like to have them. I used tape to hold things down while I experimented. Then move things around until you can get the plane to balance. For me the solution was move the motor forward and cut away part of the middle of the wing. When I was happy with the location, I installed everything except the battery. Put the plane back on the balance stand and found the final location of the battery. I needed to first locate everything else to see if I could get the battery close to where I wanted it. Then find the exact location after all of the other components were installed.
The Versa is a wonderful plane and a lot of fun to fly. For a trainer plane, I'd recommend the Storch or Bushwhacker.