I've used GDA's w/ CBL before and I would say they end up being a waste of money. Results from CBL are just as good with and they are without GDA's and not using them saves money and hassle.
When did you dose the GDA? I'm looking at night before bed vs before a high carb meal.
Both, though towards the end I just did it before bed because I got sick of trying to remember it before meals.As long as you use faster acting carbs and then maybe use some luecine to shuttle any glucose away before bed your insulin levels will fall quickly.