This illustrated guide written by Glenn Watt walks you through how to install the C. B. Gitty Part number 54-020-01, “Pre-Wired 4-String Single Coil Pickup Harness with Volume and Tone.” Cutout and drill bit sizes are given and the steps clearly shown for mounting one of these handy pre-wired pickup harnesses into cigar box guitars.
The principles in this guide can also be used for most any single-coil or humbucker pickup with a neck-through cigar box guitar, where you often have to notch down into the neck (and brace underneath it) to get the pickup into place.