We consider the problem of refined stability thresholds for multiple spots in general reaction-diffusion systems (Gierer-Meinhardt, Schnakenberg, Gray-Scott,...). The stability thresholds given by Wei-Winter (2001, 2003) provide the leading logrithm order which doesnot depend on the location. Here we obtain the next O(1) term in terms of Green's function on the locations. We then combine with Floquet-Bloch theory to study which lattice of spots in the whole space is the most stable. (Joint work with D. Iron and M. Ward).