Which baking steel is best for me?

As for the thinner vs thicker, it really comes down to whether or not, or better yet–how often you will be cooking multiple pizzas. In addition to how well a stone or steel cooks a single pizza, another true test of how effective they are is how well they handle a second or third pizza thrown on them immediately after they’ve finished cooking. This is important because cooking a pizza will drain a lot of precious heat from them. The big advantage for the thicker steels and stones then is they contain a lot of energy. This can even come into play with a single pizza.
Steel is good on any pizza but the pizza it really shines on is New York Style because the faster it cooks, the better the oven spring. The biggest benefit is between 525 and 600. You’d think the higher temperature was for the thicker steel (and all work wonderfully throughout this temperature range), but the thicker one will outperform the rest at 525 because here it’s storing a lot of energy (assuming a proper preheat, which will be longer for the thicker steel than the thinner) at the low end of NY Style’s temperature range, whereas at or near 600, it’s so hot that any will work wonderfully.