Personally I do medium sized shorts even when really confident vs. throwing an entire stack long at something. Remember you can loose more than your initial investment on shorts and carry on.
Sort of a silly trade, more for education rather than anything else. This was my first attempt at a short. Also it was sort of an experiment of shorting overnight. I had heard/thought maybe there was some interest incurred for holding a short position overnight (false) and also want to familiarize myself with the process. So, I took a small position on this slow mover, with the idea that I knew it wouldn't spike on me over the weekend. Paid 1.78 to learn a little bit, and I am okay with that.