If your dragons are 19" you should have no problem at all. They will go crazy for superworms,most dragons do. Give them as many as they want,just like crickets...you'll get the hang,just be sure to feed plenty of fresh greens like turnip,mustard ,collard [ I feed the greens first]...that is where the real nutrients come from. They should naturally slow down on the insects on their own....some people make up a ratio of how much of their food should be insect or veggie but if your dragons eat a good salad daily and are of good weight and healthy once they are mature,they will choose on their own how much of a percentage of insects to eat.That is my observation in 16 years and raising 1000's of them.If any beardie does begin to get too chubby,just cut back on the supers to every few days for a while.