The difference between grits and polenta

In my experience the primary difference is that Calzones have Ricotta (and possibly Mozzarella) and Strombolis only have Mozzarella. In the Philadelphia area, both are folded over pizzas, basically.

Growing up, my mother made Stromboli and it was rolled, not folded. I rarely see that in a pizza shop these days, but I do prefer that in a Stromboli.

Edit: Just read systempuntoout's link to Wikipedia and it confirmed something that I was going to post and then deleted. When I was growing up, Strombolis were made from bread dough and Calzones were made from pizza dough; nowadays all of the pizza shops just use pizza dough. I remember bread stores as being the primary place to get Strombolis growing up because they were the ones that made the dough!

Yes, it depends on brand, humidity, etc. My local variety is 1:4 to 1:4.5 (polenta:water) to get to that softness level

Add nothing else until you have the polenta at the desired consistency and softness