Sled is darty and hard steering on hard trails. Thinking skis with lower keel would help. Suggestions? I also have an 850 Summit that handles better on trails. Not quite the way it is supposed to be!
You could try letting out the limiter strap and put some tension on the front shock spring of the skid. Basicly transfer some ski pressure to the rear.
If you've cranked up the center to try and get some weight off the nose I guess you could try taking some preload off the ski shock springs and/or the rear springs. Its likely to have more ski pressure than your Summit though just being a crossover vs mountain chassis setup. For the dartiness have you checked the ski alignment? Toe-in will make it darty, typically you want 1/8 to 1/4" toe-out for stable steering.