Primarily the bit about setting the saddles halfway along the intonation screw setting when measuring scale length, mainly for the Tele Precision and Jazz bass style barrel and saddle bridges. Do that and you can sometimes end up with no room to move the saddles back far enough to intonate properly and with the springs on the intonation screws fully compressed. On barrel-style bridges, with yhe barrels far back, the intonation screws can be left poking up above the saddles, making it hard to palm mute.

They need to be set near the front of the adjustment screw, so there’s plenty of room to move them back without issues.

It’s been a few years now since I read it, but that’s the big one I remember.

But mainly it’s the important things it doesn't tell you than what it does that needs improving upon.