I wouldn't worry about impaction all that much. Even if you have Aspen bedding and it sticks to the food it's not that big of a deal. I try to avoid it happening a lot but if it did I wouldn't be concerned. As Brian on Snakebytes pointed out it happens in the wild and isn't going to harm the snake. Their stomach acid is pretty serious. That sucks you can't get rats. Maybe post an add on craigslist looking to buy some rats for snake food? That being said I have a 3 year old female that lived most of her life with only eating 2 mice every other week. I now feed her 3 mice every week and am trying to get her over to rats but it's a job.