I'm sitting about 1450 or so in hover. If the model tries to nod when you do a descent, make sure the governor or throttle curve is correctly adjusted to maintain your set headspeed. It's also very critical that your engine's midrange is tuned lean enough to allow for good throttle response either via the throttle curve or the governor. I made a stunning improvement in the way my model hovers by gettign the engine tuning spot on. Other things to play with would include your head dmapers and the tension of the blades in the grips. If they're too snug, it'll induce a mast bump at lower head speeds. I wouldn't play with your pitch curve if the collective feel of the model is otherwise acceptable to you. If you're having to pull the stick back a lot in high winds to get the model down, then steepen the slope of your pitch curve below your hover point.
If the model is rolling pretty well axially, then the cause for the heading change is likely your collective timing. For good rolls and especially those the the left, it's critical leave the positive pitch in long enough to keep the model from tucking, but if you keep it in too long, you can draw the model of line or at the very least cause to to drop altitude abruptly as the model goes over on its back. The finish of the roll can be no less critical. you have to play with the timing of adding the positive pitch back in to adjust the heading of the model and get the nose set to fly out of the roll. This gets especially touchy in heavy crosswinds where you may have to keep collective in or out for much shorter or longer periods depending on roll directly WRT the crosswind direction.
If you go back and look at the program I sent you, you'll see the first few points of the mixer may have an opposite direction to help set the nose. May sure you have those correctly tweaked for your model. Also, have someone stand out on your runway as you fly high overhead and do a roll. have them confirm that your're entering straight. It's EASY to be off line, and hard to see unless you have a helper.
Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA