Re: Dimarzio FRED = ?? SeymourDuncan
As far as the sound split.......which coil you make active is arbitrary but if you are using their recommended wiring that would mean it is the slug coil (red+black wires).
Part of what you are dealing with is the nature of a split bucker. The 2nd coil affects the tone, even if it isn't active, merely by the proximity of the magnets. The other thing is that, since the most common "split" position is the neck side coil, it will sound warmer as it is farther from the bridge. It is also not slanted as a normal strat bridge pickup would be, which will also contribute to less ice-picky highs.
So to really get that, you'd need a similar coil mounted the same distance from the bridge and un-slanted........
Is there a single coil that emulates that in a normal strat position? Man, I have no idea. There are a lot of variables. Short answer is I seriously doubt it, especially in the SD line.
Your best bet is to call the DiMarzio tech line and ask them directly, but they aren't going to give you answers about SD pickups. They might be able to tell you if anything in the Dimarzio line comes close, and you could extrapolate from there to the SD line. Anything would be at best an approximation though, and you'd be lucky to find that. Nothing is going to sound exactly like that coil in that position in terms of a single coil mounted in the normal slanted strat bridge position.