I wouldn't count yourself out just yet. I have horrible handwriting, I don't even attempt to do a real signature. I just do a circle followed by some swirly things. Like the saying, Dr's have the worst handwriting, assuming that also refers to brain surgeons... Accuracy is a matter of proper practice. Playing a piece slowly even when you already know it is the key to accuracy, and my key to getting this piece to the level I want it to be. The fact of the matter is, absolutely no one is better suited than someone else mentally or physically to playing the guitar. my hand span is very small for classical guitarists, and it only slows me down a little bit.