I have found if you start bo;ts in frt then turn sled on side that rear mounts line up very easy. Put rear bolt in side then turn to other side and put bolt in then tighten all/
Look at your wear bars. If they are worn more in frt of spindle than behind spindle have easy fix. Put a 1/4 to 3/8 shim between rubber snuber and ski at rear. This puts more pressure on rear of ski, makes a world of difference.