Hi

1. There's no solid answer but try about 5-6 crickets that are neither too small nor big. Then make adjustments if the frog to maintain the frogs proper weight/size.

2. You should feed the appropriate size. If you feed them too small then the frog can lose internet. Too large and it may lead to digestive upsets. You can find the age to size of crickets online.

3. If it's at the small side of the recommended feeding to size, then feed more. If it's coming to the larger size, when it will soon be eating less, reduce it to every other day and so on. If you feed a fish or mice, these have bones and probably are digested at a slower rate, so it might be wise to leave an extra day before feeding something else.

4. Calcium and vitamins should be given at the same time because they work together. They should be used at every insect feeding to balance the Ca:P ratio. It's better to use a supplement frequently on a weaker dose of supplements than a high dose infrequently. For this reason, Repashy have made Calcium Plus. This is what I use and I've had no problems. Do not feed crickets with a commercial gutload if you are dusting-it's one or the other and if you do both you could risk toxicity. However, it is recommended to feed your insects fruit and veggies, with a small amount of insect maintenance diet.

The book you have is the best reference. It has proven to work with raising and breeding large numbers of frogs and many people have followed it.