I used to do triathlons and used tri bars. It is important to ensure that you have someone who knows what they are doing set you up on them properly. Sometimes you will need a slightly shorter stem and most people mover their saddle forward slightly when using tri bars as it offers a better riding position. Remember that most triathletes don't train all that often on their tri bars, mainly only using them when they race (and the races aren't usually that long..) or training on them specifically so they are accustomed to the position when they race. Also, don't think that your set up needs to look as low and aerodynamic as the guys in the tour de france, they are super flexible.
Hope this helps