Hi, The Quadframe weighed around ~290 gms and ~970 gms with everything fixed.

With my experience and research if you are going build using locally available Aluminium frames then for the specs you mentions you should go with either 3/4" or 1 inch SQUARE al pipes (instead of round ones). Its easy to drill and fix the components. the center frame can be fixed using a aluminium fish plate. Overall the frame should weigh less than 300gms. And you have mentioned that  you are going to use 11x4.7 props which are really larger ones. So for that I recommend you should take minimum 16" for each arm so that you can minimise turbulence. The length of the frame makes 32" from one end of the arm to the other end. Try once, make some experiments with the arm sizes. But make sure that the lengths are exact and to most accurate so that to achieve stable flight. You can use a bench drill for drilling holes.

CAREFUL WHEN DRILLING HOLES AND BUILDING THE FRAME AND ALSO WITH THE PROP BLADES. OTHER WISE YOU MAY END UP CUTTING YOUR FINGERS OR HANDS AND ALSO THE PROPS MAY BREAK. I AM TELLING YOU THIS WITH MY EXPERIENCE.

http://diydrones.com/photo/propeller-cut-injury?context=user#

All the best and have a nice and safe flight.