I usually use two different flour mixes unless a specific recipe calls for different combinations.
The first is the traditional rice flour mix based on Bette Hagman's mix.
2 parts rice flour - I use both brown and white
2/3 part potato starch
1/3 part tapioca starch
I use this mix for cakes and scones.
The second is a mix that I've altered slightly from Annalise Roberts Bread Flour Mix B.
It consists of
1/3 part millet
1/3 part sorghum
1/6 part corn starch
1/6 part potato starch
1/6 part tapioca starch
It's rice flour free but I find when making my English Muffin Loaf it does call for 3 cups of flour so I often add a little rice flour mix to even it out.