For a 2 cup recipe, try mixing 1 cup white rice flour, 1/2 cup buckwheat flour and 1/2 cup sorghum flour. I'm using roughly those ratios for a banana bread tonight for a heavy carb-up. I'll let you know how it goes. You could use some tapioca starch in there, too.
Don't put your trust in anyone on this forum, including me. You are the key to your own success.