1. When a beardie is in shed mode, you will clearly be able to see as they skin will become dry and you will see bits of dead skin lying around the vivarium. As for there eyes, i haven't ever noticed it in any of my own.
2. When feeding a Beardie they should be given a fresh bowl of salad, AT LEAST every 2 days, even better if you can do it everyday this means the salad will be fresh and better for the beardies health. And insects should be given daily, (if you're using locusts for example, put 1,2 or 3 in depending on the size of the locusts AND your beardie) preferably in the morning.
3. The salad should always be more important, it has more nutrition than the insects, but if you are feeding the insects salad, then your beardie will be getting the salad through eating the insects. But yeah, always prioritize the salad. So probably a 70% veggie and 30% insects (protein)
Also you will need to use the calcium substrate (which is a powder) on the beardies salad, to help maintain a healthy calcium supply for him/her. And as you know there always needs to be a bowl of fresh water for the beardie to enjoy.
Hope this helped!