What is F Spacing? Do I need 50mm, 53mm, or 49.2mm?

F-spacing refers to a wider string spacing at the bridge. This would be used for any Fender style guitar to provide for proper pole alignment underneath the strings. A typical F-spaced set would be 52mm or 53mm at the bridge and 50mm at the neck. If you do choose to use the 53mm your ohm reading will increase but apparent output will not. The number of turns is the crucial factor and they do not change to compensate for the increased ohm reading.