Intonation changes? Think electrics and adjusting the saddle individually for each string. It is a fact that csa, tensility and other string variables can affect the intonation but look at the twelfth fret on a fan fret and the angle v csa going in each direction frets and you can see what is meant.

As I said, the long bass length and shorter treble length are my reasons for being a fan (sorry) but by coincidence, my academic claim to obscurity was concerned with mechanical vibration so fan fret seems rather logical from a pocket calculator sense too. (So does carbon fibre body, so if ever Rainsong make a fan fret, I'll part exchange my beloved Rainsong OM1000.)

Any road up, I'm back in Blighty so if BWM can get a 24hr pass, might see you in Belton on Wednesday?