I14T sailing problems

Should be more like as loose as possible, as in to give the mainsail the most forward thrust angle without quite letting the sail flap. See the below excellent video on a i12s, and note the leeward shroud loose and letting the sail heel rather than the boat. Note he has one foot straddling the fin pedals to keep them in a vertical down daggerboard position. Overlooking that seems to be the most common mistake I see on other youtubes - don't let your mind wander and let the fins spread upward. Maybe you can install the other fin drive and use bungee to keep them in down position. The more lateral area the better but it's fore and aft location could give unbalance and affect steering. The i14s has a relatively smaller % sail area, but should act like the i12s in terms of favoring "into the wind" (50-80 degrees off) because there is otherwise no boom to keep a nice shape in side winds and tail winds. Lot's of mods you can do, but something else is the problem now.