first, check to make sure your fra is bolted in the correct position, not backward.
make sure your w arm isnt in upside down
what shocks did you install when you rebuilt the skid?
have you shimmed your front skis
have you aligned your front end, any change will throw off front end. if the skis are aligned correctly, front ski preasure will have little to do with darting.
have you shimmed your skis?
what is your total gap on the rear rods, what is the spacing top and bottom with you sitting on the sled
when you sit on the sled, does the front end lift at all.
some of these questions are a little simple i know, but always check the basics.