Regardless of trajectory, always use the same stance, setup and grip; just change your ball trajectory and swing length
When chipping off a downhill lie, the most important tip is to level your shoulders to the slope of the ground so that your club makes contact at the ball
When you begin your puttting practice start by dragging two footers into the cup without a backswing, this is going to make you concentrate on keeping the face square and give you the confidence of watching balls go into the hole