I tune everything to it, if I’m using either the dissonant string or physical modelling modes… the movement of the harmonics in those modes is quite hard to predict, so I find it easiest to set structure to about 10:30, where it’s easier to pick out the fundamental, and then add harmonics from there. If you tune in one mode and then switch to another, the harmonic content will be different, so you’d probably have to retune.