I'm new to making pies and want to adapt a recipe I've recently used (uh, 3 times in the last week and a half in experimenting 
) for a 4th of July picnic. It's a basic Jell-O free fresh strawberry pie: (strawberries,divided in half with the half being mashed, mixed with water, cornstarch and sugar and boiled until thick, then poured over the other half of whole strawberries that are placed in the pie crust) that is served with whipped topping. I found that cooking the berries long enough (almost until it turns into jam) that the glaze thickens enough. But I found in my TOH cookbook that I can substitute quick cooking tapioca for the cornstarch and want to try that instead.
So my question is, do I use it exactly as I've used the cornstarch? The cookbook did say the amounts stay the same and I'm to let it sit a bit, but do I cook it like I did the cornstarch? Or do I not need to cook it?
Also, I'd like to make it a patriotic pie by adding blueberries. Would it taste okay if instead of using, say 2 quarts of strawberries divided, if I used 1 quart of blueberries and 1 quart of strawberries and divided them as the fresh berries on the pie crust and the berries cooked in the water, sugar, tapioca (instead of the cornstarch).
I'd experiment on my own, but it's getting kind of close to the 4th to be experimenting beforehand! (and believe it or not, we're getting kinda tired of pie right now!)
Thanks a bunch!