My husband has celiac disease and absolutely will not eat anything with tapioca flour in it. He can detect the taste and just will not finish his bite of food. I used to mix my own blend of flour but lately I have been using Bisquick entirely. If I am running short of it I add cornstarch, millet and sorghum to it. Unfortunately, my solution to my husband's refusal to eat a lot of things is just to make the pie fillings and serve them as a pudding, custard or whatever without any crust at all. I really miss my crusts, though. I think your pies looked delicious!