war slings would be longer.
'peace' slinging in the balearic islands mainly consists of target shooting at 20&30 metres.
War slinging would have mainly been at much longer distances, so the slings would have been longere.
It's said that a balearic slinger would carry three different length slings, for different distance slinging.
The longer slings would most likely have been for smaller ammo as well.
Plenty evidence that they used lead glandes (I have an historic lead glande from ibiza) so the pouches would have had to be smaller and the slings more flexible.
So, yeah - not a hard question to answer