I am going to barbecue 1/2 chicken on a gas grill. I want to use a water mixture with cider vinegar and salt, to baste while grilling. Can you give me any tips as I do this, like time and temperature? 
Maybe you need to buy a new box of baking soda or baking powder? Baking soda & baking powder can & do lose 'oomph' over time.  Otherwise try chilling the dough for at least 4 hours before baking. Chilling the dough usually helps butter/shortening based cookies hold their form a tad bit better. 