yes that is an interesting test to do but only if you can do it in one day, or make sure that the conditions are comparable so that numbers are matching.
if you must test on multiple days make sure to do a baseline run so you at least know if conditions are comparable.

back to the roll stiffness subject it self.
when i wrote about balanced roll stiffness i did not imply that a 50% split will be optimal. In real cars for example a good estimate value seems to be:
%Fwd rollstiffness = %fwd weight distribution + 3% to 5%
so far i've seen mixed results on this for rc cars though i haven't tested this exclusively.