Putting an Dimarzio Pickup in a Parker.
Not much help but-
The DiMarzio catalog does state, in the supplement section, in italics after the list of pickups: "Many models of Parker Fly replacement humbuckers are available. Please call for details"
Now you and I both have NiteFlys- have you noticed any difference in the pickup size? To me it looks the same, but maybe it's best just to give DiMarzio a call.
I still like the Breeds in my DBK the best, but I was playing the Parker last night, and I love that humbucker in there- very spongy, vowel-like, and harmonics were all over the place- a very dynamic pickup! Do you know what this "custom wound" DiMarzio is closest to in sound (e.g. a Paf Pro?)?