It's difficult for CODACA to recommend a specific minimum spacing between inductors. Electromagnetic fields created by inductors generally interact only with metallic surfaces or other inductors in close proximity. However, the extent of interaction between inductors depends on the current (frequency, waveform shape and magnitude ), the orientation to each other, and the distance between inductors. (Remind: Orienting the axes of inductors perpendicular to each other, rather than parallel, to get a minimum interaction.)