just my two cents nate,
i just made the switch from live to f/t, wasn't even sure it'd work. stuck two frozen rats in a plastic bag, heated it up by sitting them in hot water, made sure i could feel their ribs and to the touch they were not too cold, took them out and held them with tongs up to a lightbulb that had been on-spent most time with it near the head, moved Aza's hide and dropped it in next to her, did the whole dance thing with the tongs after lightbulb heat signature bumping with Eden and struck right away. i think the key is definitely the body temp overall and doing the little bump with the head temp via a lightbulb nearby. worked well, eden constricted it forever and finally swallowed. did the same with another rat and same thing. Aza took longer to smell it out but then just swallowed it. worked out well. conclusion: light bulb by the head.