Help with my Custom Order Description

[csacwp]

Hi everybody, I'm normally a Dimarzio guy but I've come to SD in my time of need. I am custom ordering a 7-string dual-blade single coil-sized humbucker for a custom build I'm having made. If the guitar were a six string, I'd be installing a Fast Track 2. How should I describe the pickup I want to the custom shop so that I get something with the same or very similar sound and output? And no, Dimarzio won't make me a 7-string Fast Track 2... Already checked.

Thanks in advance!