I have found chalk to be less than ideal here in the humid southland. It is hygroscopic and will attract moisture resulting in, eventually, rust. This is from experience. As we all know rust is the death of any file. After use I spray my files with WD-40 which does a good job of keeping moisture at bay, I have had zero problems in the last several years using the WD-40. I don't use any cutting oil when draw filing. I might try it next time, it won't be bacon grease though, sounds messy, and has loads of salt in it.
Alvah, those curls are fine, keep at it, even pressure and not a lot of pressure, let the tool work for you.
dave