About the crash, could you post this in the bugs section, and also tell us what resolution each of those 225MB files is?
Memory used - cache size, set this at max.
Memory used - during rendering, set this as normal. I had crashes when using "high" here, AlexandreJ advised me to use normal.
Detection - high, of course. Takes longer, but finds better matches.
You want to have your temp dir on a separate hard drive, or a RAID array would be even better. This will influence only speed, not quality.
Lastly, do you think you could upload somewhere 1 sample uncropped photo from those cameras, for our own amusement?