Sarge jigdo versions

[Diepeveen, Jos]

Hi,
In starting the download of 'sarge' CD images via the jigdo-mechanism, I saw that 
there are various versions of the first image: sarge-<platform>-1.jigdo, 
sarge-<platform>-10.jigdo, sarge-<platform>-11.jigdo and sarge-<platform>-12.jigdo.
Why that many versions? And which to choose?
Thx.