A hermanni can grow up to around 3 kilo's in weight.
For excellent care go to www.tortoises.net If you have seen them in a pet shop, please don't buy from there as they are imported more often than not and most are actually wild caught
You will need outdoor accomodation with access to heated areas so an electric supply outdoors is essential too.
Hermanns tortoise are fed on weeds such as dandelions, sow thistle, plantains and clover.
Hope this helps