Yes, I also recommend using everyday short form of signature. However, the pamphlet that comes with the passport suggests to put a true and full signature of the holder. So, what is it? The answer would be - nobody cares. The whole confusion arises from the fact that the concept of signature in the American culture is somewhat messed up. It was a long tradition here (espcially for those coming from the WASP background) to sign ones full name legibly in cursive. In other cultures, including many European ones, people simply put some illegible scribble as a signature. For one, in my home country signing your full name in cursive would be considered retardedPut the one that you use everyday, checks DL etc.