I've just ordered a second one of these after fitting one in my fretless Jazz. I used a Stingray scratch plate as a routing template to get both the 'sweet spot' and the right sized rout. It looks to be identical in size to a 'standard' Musician pickup, as the scratch plate is a lovely snug fit around the pickup.
There isn't really any information on wiring it up, so I had to get my meter out to check which coil is which; not even a sheet of paper in the packet...
Wiring is as follows:
Red wire is HOT for J coil
Thick Black wire is GROUND for J coil
Thin Black wire is HOT for MM coil
White wire is GROUND for MM Coil.