J.S.
My vote is for any way you want to spell it....either way, most people are going to ask if it's with one "L" or two. My nephew, however, spells it with 2.
My parents argued about my name until it got to the point where they just did not talk about it at all....so after I was born, my dad was at the phone in the hallway (42.5 years ago, mind you) telling his mom that my name was Janet. Mom was in the room, however, filling out the forms, so my name is actually "J." (pronounced "jeannette". Guess you could say that she won, in the end! :)
Congratulations, and good luck! (And I guess if it comes right down to the wire, you can always flip a coin for the spelling!)
~J.~