When I, and probably you had a starter given to us it was literally the equivalent of a handfull of mixture in a bowl, maybe about the same quantity as a small bowl of porridge.
If you have way too much I don't think it'd be a problem for you to divide it and share before using part of it as a starter for ten days. The idea of the starter is that it can be kept and added to for a long time. So, use a similar amount as what you got given previously and share/ ditch the rest.
Hope this helps, let me know how you get on. On the top right hand side of the page is a link to my other herman site where you can submit a photo for the gallery. Feel free if you have the time...