Alright, so I'm going to be getting a guitar from Warmoth pretty soon (7-string explorer) and I'm going to be putting a Kahler trem in it.

My question is this - is the cavity for the 7 string Kahler the same as the 6 string version?

I've looked around online, and there doesn't seem to be any information about it.
Okay, cool.

Any idea on how much bigger the cavity will have to be? Or would there be some site where I could find the info on the size?