I am afraid your buns will turn out being overdone if you bake them for 45 minutes. 12 - 15 minutes for buns and 30 minutes for a bread is ok.
I am always baking buns myself and I would suggest that you add psyllium husk powder (a table spoon) for your recipe. You could also add oat to make the bread more healthy and tasty. And replace the baking soda with yeast, if you don't want to avoid yeast for some specific reason.
Finally a tip: always start with the luke warm water, then add psyllium husk powder, let it rest for 15 minutes, and add the rest. If the dough is getting too dry / hard, add more water and mix the dough, you are not supposed to work the dough as we do with gluten doughs, because there's no gluten to activate by thorougfully working. The psyllium husk powder is making the dough stick together and not fall apart. So psyllium husk powder is of great importance in a gluten free dough. /read lables, the mix could already content this powder.
Sugar, salt, nuts is making the buns yummie.
Here's a good link that explains what I am talking about