what are pickup spacings, i saw on a DiMarzio X2n there was a f-spaced one and another one. what is f spacing and what is the spacing on Epiphone guitars (goth flying v if it makes a difference)
Your Epiphone V needs an F-Spaced pickup. This is from Dimarzio's website.

How do I know which spacing to use?
F-spaced pickups measure 2.01" (51 mm) center-to-center from the first polepiece to the sixth. Standard-spaced pickups measure 1.90" (48 mm). Although some players believe that F-spaced pickups are only for the bridge position of tremolo bridge guitars, many
guitars with fixed bridges (including late 1990s Gibson Les Pauls and Epiphone LPs) should have F-spaced pickups in the bridge position. Most tremolo equipped guitars that have a nut width of 1-11/16 (43mm) or more should also use an F-spaced pickup in the neck position. If you’re replacing a bridge-position pickup and you're not sure what your
string-spacing is, it's usually better to get an F-spaced model. It is not necessary for the strings to pass exactly over the center of the polepieces for best performance, but it is wise to avoid a situation where the E strings are sitting completely outside of the outer polepieces.
Seymour Duncan calls their version Trembuckers.