Re: pup for narrow string spacing.
I have a guitar with 52mm string spacing at the bridge and a 43mm nut. A DiMarzio "F-spaced" pickup aligns perfectly in the bridge with a regular spaced model in the neck. I've used Seymour Duncan Trembuckers in it, as well, and they are pretty close, though not perfectly aligned if you look straight on.
Ultimately, you can get away with either F/Trem-spaced or G/Standard-spaced and won't notice any difference in tone. In case you didn't know, there was a 10-year period in the '70s/80s where almost all of your wider spaced bridge guitars (guitars with Floyd Rose trems, Fenders, many imports, etc) used regular spaced pickups as stock and had no issue sounding great.