The Exerted torque for each joint

Hello,

I want to make AR3 as graduation project .

I have a problem, as in our country we don't have variety in motor (small range of powers ) , there are only few kind of motor in the markets . so can you tell me the needed torque value at each joint , to try to modify the stander design to match the existing motors .

lets see the outer dimensions of my robot is same of stander dimension .

I know it depend on the structure material used also by the way .

thanks