My favorite brand of super firm tofu is Wildwood.
I find that freezing and thawing tofu before cooking improves the texture pretty significantly. You can certainly skip this step if you’re pressed for time, but I think it’s key to the final texture.
If you’re trying to limit your sodium intake, you could opt for low sodium soy sauce in this recipe. I do think the saltiness makes a difference in optimizing palatability, but it would still taste delicious.