One of my goals on determining cross/main tension differential is racquet distortion. Measure your racquet dimensions after you cut out the old strings and BEFORE you mount the racquet on the stringer. Then measure the dimensions again after you complete the string job and remove the racquet from the stringer.
How much distortion are you getting? On my racquet a 2lb difference results in virtually no racquet distortion. The less distortion, the better my stick seems to play...
Head YouTek Prestige MP (18x20) - Wilson Nat Gut 17/MSV Co-Focus 1.18
(58/56) - Gamma X-Els