Soak the noodles:

Place 7 to 8 ounces dried pad Thai noodles in a large bowl and add enough lukewarm water to fully submerge the noodles. Let soak until the noodles can bend around your fingers without breaking, about 30 minutes. Meanwhile, prepare the tofu.
Prepare the tofu:

Fit a rimmed baking sheet with a wire rack and line the rack with paper towels or a kitchen towel. Drain and cut 7 ounces extra-firm tofu into 1/2-inch thick planks. Place the planks in a single layer on the towels and sprinkle with 1 1/2 teaspoons kosher salt. Cover with more paper towels or another kitchen towel. Top with a second rimmed baking sheet. Place some heavy weights on the baking sheet (a Dutch oven plus your bowl of soaking noodles makes the perfect press). Let drain for 30 minutes. (Skip this step if you are using a tofu that is not stored in water.) Meanwhile, make the sauce and prepare the remaining ingredients.
Make the sauce:

Place 1/4 cup palm sugar paste, 3 tablespoons fish sauce, 3 tablespoons tamarind concentrate, and 3 tablespoons water in a small saucepan and bring to a boil over medium-high heat. Reduce the heat to medium-low and cook until the sugar is fully dissolved and the consistency of maple syrup, 2 to 3 minutes. Remove the saucepan from the heat.
Prepare the remaining ingredients:

Mince 3 garlic cloves and 1 medium shallot (about 1/4 cup), and place both in a small bowl. Finely chop 1/4 cup preserved radish and crush or coarsely chop 2 tablespoons roasted, unsalted peanuts. Place both in a second small bowl. Rinse 2 tablespoons small dried shrimp and add to the bowl of peanuts and radish.
Crack 4 large eggs into a medium bowl. Halve 2 medium scallions lengthwise, then cut crosswise into 1-inch pieces (if using 6 garlic chives, cut crosswise into 1-inch pieces). Place in a second medium bowl and add 2 cups mung bean sprouts.
Drain the noodles. Transfer the tofu to a cutting board and cut the planks into pieces roughly 1 inch long and 1/2 inch wide. Pat 8 ounces raw jumbo shrimp dry with paper towels if they are very wet; you can keep the tails on or remove them.
Cook the tofu and shrimp:

Heat 2 tablespoons vegetable oil in a large, well-seasoned wok or nonstick or cast iron frying pan (12 to 14 inches) over medium-high heat until it just begins to smoke.
Add the tofu and stir-fry until golden-brown, about 5 minutes. Transfer to a large bowl, leaving the oil behind in the pan. Heat the pan up again over medium-high heat. Add the jumbo shrimp and spread into a single layer. Cook until opaque and just cooked through, 2 to 3 minutes total. Transfer to the bowl of tofu.
Cook the noodles:

Add the remaining 2 tablespoons vegetable oil to the pan. Add the shallots and garlic and fry until fragrant, about 30 seconds. Add the peanut mixture and cook until fragrant, about 30 seconds. Add the noodles and sauce, and keep the noodles moving in the pan (use 2 spatulas if you can) until the strands are cooked through and evenly coated in sauce, about 3 minutes. If the pan dries out before the noodles soften, add water a tablespoon at a time (2 to 3 tablespoons total) and keep stirring until the noodles are cooked through. Transfer to the bowl with the tofu and shrimp.
Cook the eggs and combine:

Return the pan to medium-high heat, adding a little more vegetable oil if the pan is dry. Once the pan is starting to smoke again, add the eggs. Scramble the eggs with a spatula to form large curds. Right before the eggs are cooked through, return the noodle mixture to the pan and toss everything together, breaking up the pieces of egg.
Finish and serve:

Push the noodles to one side of the pan. Add the scallions and bean sprouts to the other side and toss into the noodles until just wilted, about 30 seconds. Transfer the pad Thai to a serving platter.
Serve with lime wedges, 1 to 2 whole medium scallions or garlic chives, a handful of fresh bean sprouts, a banana blossom, and small piles of granulated sugar, crushed peanuts, and red pepper flakes if desired.