As an S/O you are much better off on the Bus..... you wont be doing any flying, so it's best to be on the fleet with the least amount of uptight wankers. The 744 has a large percentage of them..... so you are much better off being on the Bus to start and moving to 777 when you upgrade.
Congrats on the job! It is a good company to work for, as long as you do your job to the best of your ability, then go home and forget about work, crack a beer and stay out of DB!