The GSmini is "7/8ths" the size of the full GS body. Likewise, the Baby Taylor is often referred to as "3/4ths" the size of a full dred body.
FWIW, I'd generally agree with these descriptors. The GSm really isn't that much smaller than, say, a full-sized GC Taylor; and the "Big Baby" scarcely smaller than a full dred. While the Baby T really is pretty small in every dimension, particularly the neck's length, thickness, and fretboard width.
Edward