Can I mix all-purpose flour with high-gluten flour to make bread flour? Basically of the opposite of this question.

I'm writing during the 2020 pandemic, and bread flour is sold out everywhere because everyone (including me) is entertaining themselves at home by making bread. I did manage to find "high-gluten flour", which according to Epicurious seems to be more or less the same as bread flour but with a higher protein content:


  Unbleached all-purpose has the lowest amount of protein, usually around 10.5%. Bread flour contains about 12 to 12.7%. High-gluten and whole-wheat flours have about 14% protein.


My recipe calls for white bread flour. (I'm making sourdough at 80% hydration, in case it matters.) Can I get there by mixing this high-gluten flour with AP flour? What proportions should I use? Any pitfalls I should be aware of?
Yes, you can mix them at basically a 1:1 ratio to achieve a flour with roughly 12% protein content (mimicking bread flour).

Bread flour is milled from hard spring wheat, which has a higher protein content than the hard winter wheat used in all-purpose flour. Protein adds strength to dough and enables loaves of bread to rise high.

Mixing them together to achieve a roughly 12% protein content will ensure you don't end up with a bread that's way too dense/soft or rises far too much/little, basically.

There's no issues mixing flours, and in fact this can be a great way to create the mixture you need when it's sold out (such as during this pandemic).