UPDATE: Spent this past season using hopper mice on difficult first time feeders. We went with f/t to better ease the transition the rats in the long haul and it's worked like a a champ! We have been feeding the mice for a couple of weeks and then scenting rat pinks to switch them over and generally, within a feeding or two, they have switched right over. I guess at that small a size, the feeding response is strong enough that they don't have as much trouble switching prey.
Thanks for all of the advice guys! PROBLEM SOLVED.