What can i sub the potatao starch? More tapioca, or …

Name: Gluten-Free Vegan Bread Machine Loaf
Prep time: 15 min
Cook time: 1 h 10 min
Total time: 1 h 25 min
Cuisine: Gluten-Free
Ingredients: 1 cup buckwheat flour (120-130g)1/2 cup white rice flour (70g)1/2 cup brown rice flour (70g)1/2 cup tapioca flour* (60g)1/2 cup potato starch (70g)1/2 cup seed or nut flour** (50-60g)1/2 tablespoon fine grey sea salt (8g)1 tablespoon organic coconut palm sugar (or maple syrup) (10g)2 tablespoons whole psyllium husk (14g)2 teaspoons active yeast (10g)1 cup warm water*** (240g)1-1/4 cup homemade hemp milk**** (300g)