I think mixing those two particular flours would work okay. The almond flour may be a bit heavier than the soy flour. You might get some xanthan gum powder and add 1/8 tsp to your recipe to lighten it up a bit. Xanthan gum is a natural product made from seaweed.
My experience with these kinds of flours comes from being born with a condition called non-tropical celiac sprue, which means I cannot eat gluten-containing grains such as wheat, rye, barley, spelt, kamut, etc.
You might check out some of the gluten-free flour mixes at
www.kinnikinnick.com. Sometimes these are available in local health food stores as well. Kinnikinnick makes a Brown Sandwich Bread with brown and white rice flours, tapioca starch, flax seeds, and pea protein/fiber. The bread is vitamin-fortified and one slice has 70 calories. Not 100% "clean," but typical whole grains, aside from rice, are not an option for me.
I find these pre-made GF breads are very good in moderation for convenience, for lunches. GF breads are very dense and I never want two slices - I eat all my sandwiches open-faced. This bread is much better when you toast it (med. dark to dark) before applying your toppings. For dinners, I have more time to cook brown rice or quinoa pilafs, etc.
HTH,
Kristina
