Marie,
When you find yourself involved in something that requires the use of a rebreather, then is the time to truly research, find the system that will best accommodate the situation and then train.
Otherwise, just get some general information on the types and basic components required for rebreathers and add that to your growing knowledge base. You can find some great information on the Internet and a couple books that have been published. Also, study diving physiology, begin with Nitrox and work out from there.
Nothing wrong with doing a little research. I applaud anyone trying to increase their person knowledge base.
CrazyC