If you’re having trouble with your gluten-free scones being too dry or crumbly, things that you should focus on are: 1. The amount of oil - too little oil can make them too dry, but too much can make them crumbly. 2. The type of gluten-free flour you’re using. 3. Although xanthan gum does help with gluten-free baking, I don’t think it’s necessary to use for this gluten-free scones recipe. 4. The consistency of the dough/the amount of milk you use - if the dough is dry, the scones will be even drier!