I would say no sand at all, beardies have the tendency to lick things in order to taste what it is, they will keep on tasting stuff over and over. Impaction is deadly. My beardie gets 5 crickets in the morning and 5 in the evening, then some bearded dragon kibble and fruits and veg. They amount of crickets you feed stay the same they just get bigger as the beardie grows, overfeeding can kill them and too big prey will lead to paralysis. They do not always take to food the first time and only learn later on that it is edible so keep on offering. If it seems like it is moving it might 'inspire' them to eat it. Mealworms may cause them to die if fed on them too much, they are strictly a treat. Although they love worms of any kind!!!!! Roaches are good too. Crickets provide fibre, mealworms or superworms fat and roaches protein. (Superworms are preferable as they are apparently softer than the mealworms.) So mix it up a bit. I bath mine onece a week and then wash the bath with Domestos and hot water. Whenever their stomachs are not going a lukewarm bath does the trick. They need natural sunlight and their behaviour changes a lot after a "tan". They get busy and alert. Sometimes on a hot day I let him bake on the grass and then but the sprinkler on which is too cute as he tries to swim on the grass.
I got mine to drink water by using a syringe dropping a drop of water on its nose every few mins. Like I say if anything moves they will try it out so you could take a polystyreen cup and make a really small hole in it and pour some water in and let it drip on a waterdish which is not standing completely flat. They cannot drink like other animals so they need to be able to lick it off.
They can become really spoiled regarding food and sometimes even bored, in fact they might stop eating their old food if they are bored with it. They do not need the red lamps during the night in summer only in winter. They start to brumate in winter when they get older and they will eat and move less during that time. The white part of the feces is their hardened urine.
Don't mistake a lack of talent for genius