I'm having a little trouble playing fingerstyle. Well, you see, when I first started about playing, I used my index finger constantly (before I knew about two finger plucking), and it built up a callous very quickly and eventually became very rough. When I play with it, it creates a sharp and trebley sound. I don't have a problem with this, but my middle finger is not very rough at all. When I play with the middle finger, it creates a dull sound, quite unlike the index finger. So when I play with both fingers, there is a very noticable difference in tone. I tried to build a callous on my middle finger by regularly playing near the bridge with it, but it's not working well at all. Is there anyway I can get my middle finger to sound rough and trebley like my index finger. I know this question was pretty lame, but any help would be appreciated.