I've built another Jerry Garcia styled guitar. This time I've made some modern adaptations. The standard pieces of the JG puzzle are Dimarzio Super 2 pickups switched to the middle position with a coil cut so it's in single coil mode. A unity gain buffer to change the standard high impedance signal to low impedance. This allows the extra cabling for the third piece which is an FX insert in the guitar. The signal would flow from pickups, to buffer out a 1/4 TRS jack to the FX, then return to the TRS, to the volume and tone pots and then out another 1/4" TS connector to the amp. By having the TRS insert cable, you've effectively placed the FX loop inside the guitar between the buffer and the volume knob. This is a great feature for several reasons.