Tiger sails on a totally different mast? No wonder you have issues with keeping up. At a minimum you should have the luff curve of the mainsail re-cut to match your mast bend.
If you have a composite tip, you will never match the efficiency of a Tiger rig in gusts. How well the leech stands is a major factor when going to windward in puffs, and a soft mast-tip will bend in puffs allowing the leech to fall off. I think Bill made a very good point.

The lift of a foil should be carefully balanced against the sailarea (or rig type) you have. If you have increased your sailarea and moved the center of the sails, you might benefit from working on your daggerboards. First check the condition of the boards (scratches, nicks, dents etc.). Playing with mast rake can also be a good thing. But matching the mainsail (and jib luff curve) to your rig is what I think will give the largest increase in performance. To give an example, when the Tornado class needed an performance upgrade to stay in the games, they added a new sail package to the existing platform. It made the boat much faster (not to windward tough, just more powerful), but the foils and hulls was never altered. So the Tornado still sails with really inefficient centerboards with a shape defined back in the 60s. It is still one of the fastest beachcats around due to rig development (mast+sails) and the sailors skills.