Be very careful if you use those grinding stones. I got a set of those a while back and on the first use the Pink stones exploded, scared me half to death. Make sure you have eye protection. The drill bits seemed to work pretty good.
I use guitar strings for several other uses in models. I made friends with a local rock band and they give me their used strings- they change guitar strings every week, or before every show. I was getting them from a local music store but they caught on and started charging me for them. If you try to get them from a music store, don't go to the same one every week.