Start with the red dough. In a large bowl mix together the wheat gluten through black pepper, all of the dry ingredients. In a bowl or measuring cup whisk or blend the wet ingredients: water through liquid smoke. Pour the wet into the dry and mix using a stand mixer or heavy spoon. The dough should be somewhat tough. Set aside.
In a separate bowl repeat the process for the white dough. Mix the gluten through salt. Pour in the water and oil, if using, and mix using a heavy spoon or stand mixer. This dough should be softer than the red.
Turn oven on to 300 F. Spray a 9x13" glass baking dish with a light layer of oil. Set aside for the next step.
Break the red dough into 4 pieces and the white dough into 3-4 pieces. Flatten each piece and layer alternating colors. This is your time to be creative. You can also use the steps as shown in the post to make a more variegated and marbled look. The goal is to have white layers in the dough solely for aesthetics.
Once you have a big block of dough place it in a glass baking dish. Lightly spray with oil and place a sheet of parchment or aluminum foil on top. Place another glass baking dish on top and press down. Load up the dish with evenly distributed weight to press it. Let it rest like this for 30 minutes. Remove the weights and place the dish with the second dish on top into the oven. Bake for 45 minutes.
Your seitan will be a bit undercooked at this point but that's the goal. Keeping it slightly undercooked makes it easier to slice and it will pan-fry better. It is pliable and you use it to wrap around things too! See notes for additional ways to prepare the seitan bacon.
Slice into thin strips and refrigerate for up to 2 weeks or freeze for longer storage. It is best to freeze in a single layer if you want to remove just a couple of strips at a time.