We have just discovered a corn (and rice) allergy in my son. I am having trouble finding substitutes when baking. For example, I have a pudding recipe that is very simple to make that takes 2 tbl of corn starch. I tried it today with the same amount of tapioca starch flour and it was rubbery in texture (though flavor was fine). I also have arrowroot. My issue is finding a good substitution guide when baking as baking is so precise in order to have success. Any suggestions would be appreciated. Thanks.