In this paper we collect and detail recent results concerning 77Se and 13C nuclear relaxation rate measurements obtained on several representatives of the (TMTSF)2X and (TMTTF)2X series of charge transfer salts as a function of temperature and hydrostatic pressure. From the temperature and pressure dependences of T-11, for the compounds (TMTTF)2PF6, (TMTTF)2Br, (TMTSF)2PF6 and (TMTSF)2ClO4, we are in a position to extract the nature, the amplitude, the statics, the dynamics and finally the dimensionality of spin correlations that characterize the unified phase diagram of both series of materials