Let the ribs sit at room temperature for about 1 hour.
Meanwhile, prepare a gas or charcoal grill fire for indirect cooking over low (300°F) heat.
Sprinkle the meat side of the ribs with 2 teaspoons salt.
Arrange the ribs bone side down in a single layer over the cool zone of the grill.
Close the lid and cook the ribs until tender, about 2-2½ hours.
To test if they’re done, insert a knife into the rib meat—if it slides out without pulling at the meat, they’re ready. The meat should be tender but not falling off the bone.
Remove the ribs from the grill and transfer to a large rimmed baking sheet lined with foil.
Increase the temperature of the indirect grill fire to 350°F.
In a medium bowl, mix the sweet soy sauce, root beer, and both chili sauces. Set aside ½ cup of the sauce for serving.
Brush the ribs on all sides with the remaining sauce.
Return the ribs to the cool zone of the grill and cook, turning once, until nicely lacquered, about 10 minutes total.
If you like your ribs more browned and with a little char, place the racks over the direct heat for 3-4 minutes per side before removing from grill.
Let the ribs rest, tented with foil, for about 10 minutes before cutting and serving with the reserved sauce for dipping or for drizzling over the ribs.
