Hello. whats the diference between humbucker and humucker in single coil size (hot rail)? is the diference only size or is there something else?
The size is different, but they also sound a little different also because of the size difference.

I use both types and I have no problems with them at all.
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
One makes you sound like Slash and the other makes you sound like Billy Corgan.