Tough question, few straight answers. I think Jake summed it up best with his statements on the rig. Most Tiger's command more than they are really worth (at least asking price, $1 or $2K more often gets you into an early Infusion), and the Tiger rig and foil package is very dated at this point. Don't get me wrong, in the hands of a competitive sailor it will still put up a good showing but the boards are the lowest aspect ratio around and the mast is a teardrop section, not a wing mast. I may be wrong on some of these points, since there were several versions of the Tiger and some have been upgraded with more modern foils and sails.

In direct comparison between an original Nacra F18 and an original Capricorn, the Cap was faster uphill but suffered going downwind. I'm 100% confident the differences were sailor ability, rig tuning and sail choice. I would stay away from an original Nacra F18. The Infusion, as mentioned above, has a modern hull shape and should perform well. It also has amongst the most hull volume of the used boats on the market (more so than the Capricorn and better placement than the Tiger) so is a good choice for the heavier teams. I voted for the Infusion over the Cap primarily because you mentioned big boys. That vote stands if you race in heavier air conditions as well. Otherwise the Cap is a good second choice.

I have no comment about the Hawk as I've never seen nor raced one.