Bob's Red Mill Gluten Free AP Flour Substitute

As I am researching gluten free bread I came across recipe using Bob's Red Mill Gluten Free All Purpose Flour. The website only mentioned what type of flour used but of course we can't tell for sure what's the proportion of each ingredients. Upon searching I found this recipe posted by Flo and Grace.

Ingredients
4 parts garbanzo flour
2 parts potato starch
1 part tapioca flour
1 part sorghum flour

Instructions
Combine all ingredients in a large airtight container or zip top bag.
Shake well to combine.
For optimal freshness keep refrigerated.

In replacement for potato starch, I used sweet potato starch and I used pearl millet flour (bajra flour). Also for garbanzo flour I used besan flour.