Use caution here Sycamore, While doing examinations of the C of G range of a number of Citabrias and Champs, I found differing C of G's and datums. Associated with this, were differing pitch control travel limits. A few of the C of G limits expressed for the floatplane were actually not achievable with possible loading configuations. On one occasion, I achieved the required aft C of G for test only by pouring water into aft float compartments.
I always work with the TCDS C of G data applicable to the specific model I'm working with.