I have done quite a bit of stained glass work. For smoothing the
edges I use a Glastar grinder, but also fine tune any ragged edges
with a carborundumstone---referred to as a carborundum file. For the
small amount you have, it will be a very effective, less expensive
method, than investing in a grinder. Every glass store used to carry
them but for some reason, they are hard to find. I was able to get
one recently from Alpine Glass http://www.ganoksin.com/gnkurl/ep7zbs
Item 2007, price $7.95. It should be just fine for your purposes.
Why my interest in stained glass? My house has an ugly cyclone fence
running along one side. I decided to make a lot a stained glass
panels to hang on it, and now it is delightful to look
at---especially when the sun shines through the glass. My neighbors
were delighted, andI can now enjoy the fence, rather tha=n shuddering
each time I look at it.