If the dough is too extensible for you, you might cut back on the water by about 1 tablespoon and see if that makes it easier for you to handle, but eventually, you'll get used to handling the wetter dough. Also, no one is going to give you any demerits for using a rolling pin either.
From a dough recipe with 500 g flour, I usually make either 2 (12-inch) pizzas or 4 (8- or 9-inch) individual pies.
As far as how thin to stretch the dough...not so thin that you can read a newspaper through it! You can stretch it to almost any thickness that you'd like, so it will support the toppings. These pizzas are usually not "loaded"...cheese, sauce, and up to 2 or 3 other items is usually plenty. If it stretches thinner than you'd like, just lay the crust down and gently prod it into a smaller circle, working into the center in order to make the center a little thicker. It's pretty forgiving.
As far as cheeses go, use what your taste buds like. Some people use sliced fresh mozzarella balls but I find the cheese a little wet, at least for the ones I have tried, but it is a matter of personal taste. Mixing cheeses is nice. I sometimes use a mix of mozzarella, white cheddar, and Asiago. Or whatever I want to use up.
Personally, I prefer to use diced cheeses (about 1/2 inch dice) rather than sliced or shredded. The diced cheese when melted makes small cheese puddles, is less likely to overcook and get stringy at high temperatures, and gives a cheesier impact when you bite into the pizza.
A light drizzle of extra-virgin olive oil (including on the exposed crust) before baking the pizza, or a garlic or herb oil afterwards is very nice.
Take notes, jot down your toppings and cheeses, and whether or not you liked the combination. Note any changes that you might want to try for the next time.
Rita