Not gonna bother with useless, uninformational, background information; I will, however, apologize in advance if the lines/"paragraphs" don't separate, the device I'm using tends to keep eveything smushed together even when attempteed to separate. 1. How many rats can fit in a single? 2. Any idea on where to order the cheapest one, double AND single? (Not together, of course!) 3. What do you think of it/what are your experiences with it?