I kind of think the default 7-string body should be the Z. They're already close. The Z looks rad but not terribly so, but the 7 string looks kinda goofy. And honestly I don't really think the Z body would put off anyone buying a 7-string. At least not a Warmoth. Yes, there are 7-string jazz boxes and teles but ... Warmoth doesn't offer a 7-string in a traditional body shape.