About experimentl methods for observing the anisotropic plastic behavior of FCC alloy

I'm doing a research on anisotropic yield criteria for a FCC alloy and I have to do biaxial tensile experiments to get the yield locus in the biaxial stress space.I have two kinds of samples: 

         1. metal sheet with dimensions of 150mm x 70mm x 15mm(thickness); 

         2. rod with diameter of 20mm and length of 150mm. 

   One approach is biaxial tensile tests using cruciform specimens with large size(usually more than 200mm in each arm in order to get an uniform stress region in the gage section of the specimen). but this approach is not suitable for my experiment because of the size limitation. The same broblem happens to the tension-internal pressure experiment with thin-walled tubular specimens. 

       Can anyone give me some advice? I really need some opinions.Thanks in advance.