I think the length of your video is good, you really don't want it more then 30 seconds. If it is to long people will not watch it all, the main thing is that you get your point across fast. I would also make the video auto play because most people will not click to start it. I know a lot of people hate auto play videos on lead capture pages but there is proven stats that say it converts better.
RE: The long or short version of video marketing?