Hey all, sorry for the delay, been a bit busy.
Here's a couple of updates: I took a cheap needle style knife sharpener (about the size of a ball point pen refill) and smoothed out the edges of the tuning machine. Then, I took an old wound string and ran it through, using it to sort of file everything a little bit more. Then, I took a length of leather lacing and did the same, picking up any metal filings that may have been left behind.
Since I had so many extra high-G-stringless sets of strings, I took one of the "ten-thou" and tightened it up to concert pitch without any problems. My twelve's playing beautifully, and I have no fear of the string breaking. Next time, I'll hook up a full set of D'Addario EXPs, and I don't think there'll be any problem.
Thanks again to everyone for all the amazing help; trust me, I'll be back here again soon!

'Bluegrass is wonderful music. I'm glad I originated it.'-Bill Monroe