Grape Filling for Pie, crumble or cobbler

When we bought our place here in the Muncy Hills, it did not have running water or other modern amenities, but it did have an apple orchard and two Concord grape vines. The hardy grape cultivars endured my how-to-take-care-of-grapes learning curve and now are reliable producers. Compelled by roadside signs advertising "Grape Pie" in the Finger Lakes and our family's love of fruit pies, my internet search for a recipe led me to a blog post by Chism Heritage Farm. I love reading the story of Aunt Marian and with adjustments made to her pie filling recipe to accommodate for our preferences, we enjoy all of the fragrant grapes from our sturdy vines.

Grape Pie, with notes outlining my adjustments.
5 1/3 c Concord Grapes
1 1/3 c Sugar (I usually add about 1/3c. less of sugar since the grapes are usually sweet enough)
4 T Flour (because of the celiacs and my preference for a clear fruit pie filling, I use instant tapioca to thicken my filling. I measure the amount of filling and follow the directions on the side of the box for blueberry fruit pies.)
1 1/2 t lemon juice
Dash of salt
1 1/3T Butter
Remove and save the skins from the grapes.
 I squeeze the pulp right into a small saucepan.
Put pulp into a saucepan without water and bring to a rolling boil.
While hot, put through a strainer to remove seeds.
 I usually put the strained pulp right into the bowl with the skins.
Mix strained pulp with skins.
Mix with sugar mixture (and flour, salt and lemon juice) and put in crust in 9" pie pan.Dot with butter
 Instead of the flour, I add the correct amount of instant tapioca. I stir it and let it sit for 15 minutes, per the instructions on the tapioca box.
Bake at 400'. At this point, the filling can go into a pie crust or under a cobbler or crumble topping.
For a crumble I butter the baking dish before adding the filling and top with a nut/oatmeal/butter/sugar topping. I do not add spices to the crumble topping but I sometimes toast the nuts before chopping them. 
If the filling is for a cobbler, I stir my final  grape mixture in my cast iron skillet. When spooned on top of hot filling, cobbler dough doesn't seem to get "gummy" on the underside when it bakes in a hot oven.

The prepared filling freezes well.