I wanted to convert a banana bread recipe recently and found a blog post that recommended 1 lb white rice flour whisked with 1/2 cup tapioca starch. I had bought some sorghum flour, so I substituted sorghum for 20% of the white rice flour. Sorry for the annoying mix of measurements - I haven't posted the recipe because I would have to do it again to report everything in grams and cup measures.
https://www.thekitchn.com/glutenfree-baking-how-to-make-132517

Anyway, it came out delicious with a velvety pound cake texture. Maybe I'll make the mix again for this recipe, which looks yummy!