Baking with unmalted bread flour

I'm almost out of my usual King Arthur bread flour, and it's proving rather difficult to get more. I happen to have a 5 lb sack of Heartland Mill no-additive strong white bread flour lying around that I bought a while back to try to bake for a friend who's deathly allergic to barley malt. What changes am I likely to need to make to bake yeasted bread with this? What about sourdough bread? I know that sprouted wheat flour doesn't have as much amylase as malted barley flour, but I do happen to have some of that on hand too. Would it be worth adding some of that? If so, how much?