This may be a stupid question, but how do you time how long it should take to walk down the aisle and how long the processional song should be? I'm planning on just playing the music off a CD and I really like a piece of music that's about 4 minutes long, but 4 minutes seems way too long when the aisle I'm going to be walking down is quite short. Also, how many songs do you need for signing the register, how long does that usually take (including people taking photos etc?)