In order to quantify the similarity of structure and dynamics in the different alignment media (homogeneity of RDC data), a SECONDA analysis was applied (Hus and Brüschweiler 2002; Hus et al. 2003) on the methyl RDCs. The SECONDA ratio of the 5th to 6th eigenvalues gave a reasonable value of 2.83. The fifth eigenvalue of the diagonalised F-matrix was 0.53.