Don't use a forward post. Keep your seat angle at 73-75 deg for power transfer. Any steeper and your power starts to fall off. You'll be sitting up in a pack so your hip angle will be open and you won't be taxing your legs too much for the run. Regarding the mini tt bars, it all depends on whether you think you can run for the win or you need to get in a break on the bike. For pack riding, you won't use them. If you're in a break off the front (or miss the lead pack out of T1 and need to bridge), you may want them.

You can get a good idea of bike set-up from looking at the ITU pros. If you're a runner (as I believe you are), set it up like Gomez, Witfield, et al. If you're not, set it up with mini bars and hammer.

What you see in World Cup races is going to be a lot different from what you see in Continental Cups and what you'll probably see in Twenty-12. In World Cups, there's a huge trail of guys coming out of the water and everyone is settled into a pack within a minute. The Continental Cups and Twenty-12 will have a lot more individual effort involved.

Most likely, you'll be near one or two other guys out of the swim, and you'll all be going 30-35 mph out of transition and form into a small group in the first few hundred meters. Then several small groups will start coming together in the first couple miles. Until the big group forms, having some aerobars will be very helpful. If you can't hang onto 30+ mph for several minutes, you're going to get shelled. While running aerobars on a road bike is nowhere near as fast as a tri bike, at least it helps.

And make sure you're doing plenty of anaerobic and hill work. The group will be putting out 500-600 W on every hill and out of every turn. Draft-legal is pretty brutal, but it's LOTS of fun.