DSGB,
Okay, I can understand not wanting to learn sexing on a chondro. About how much does your animal weigh? I just want to get a feel if we are dealing with an animal that is a couple years old or something bit older.
Also, forgot to ask, do you know locality?
It seems unlikely but the flashlight might irk the animal enough to keep it from feeding. Might be worth looking into... If you can get a hold of one consider using a CF blacklight in a lamp in the same room. Should give you just enough light to see by and not disturb the snake too much. If you can not find a CF black light I might be able to hook you up with one if you can swing by Tech...
Maybe I missed it but did you say if you heat the F/T once it was thawed? These guys will really key in on heat (note, do not try feeding after taking a hot shower, that is asking for trouble.)