In a large bowl, whisk flours, tapioca starch and salt. Add grated lard and, using your fingers, gently mix and rub it in until the mixture resembles fine crumbs with a few larger pieces.
In a measuring cup, whisk water, vinegar and eggs together. Pour over dry ingredients, stirring briskly with your fingers until some kind of a ragged dough starts to form.
Turn onto a working surface and gently press into a ball.
Cut into 4 wedges and, while being careful not to overwork the dough, form each wedge into a disc. Wrap in plastic film and refrigerate until chilled, about 30 minutes (At this point, you can safely refrigerate the dough for up to 3 days.)
Take pastry out of the fridge at least 30 minutes prior to rolling it to give it a chance to come back to room temperature. This will help it roll better and not crack so much.
Roll out pastry between 2 sheets of parchment paper. Take care to flip it over from time to time and when you feel that the dough starts to adhere to the paper and not expand all that good, peel the paper off, scrape it clean with a plastic scraper if necessary and place it back over the dough.
When disk is large enough to fit into your pie dish, slide it with the parchment paper onto a pizza plate. Peel off top paper and place pie dish over the dough. Flip the whole thing upside down so the dough falls right into the pie dish. Peel off parchment paper, reposition dough if necessary and fix inevitable cracks and breakage.
For top crust, if using, simply turn the disk over the pie filling while it still has the bottom parchment paper attached to it, then peel it off once the disk is in the right position. Press down and seal both layers by pinching the edges together. For better adherence, brush the bottom edge with beaten egg, coconut milk or a mixture of both before adding the top layer.
Brush egg / coconut milk mixture all over the top crust (if using) and bake in 400°F oven for about 18-20 minutes or until golden brown.