Tom S, if you went with a dark enough roux, you could probably get a good roux flavor to the crust with as little as 7%. Combine 7% and a very high gluten 14% flour and the dough should rise just fine. Just make sure you don't add any additional oil or sugar.
Otherwise, and I'm sure this has occurred to you already, but if you add roux to the sauce, the taste will be far more prominent.
And, far be if for me, a Yankee, to tell a Southerner how to make roux, but, if you're going to use oil, you really should add it at the beginning. Oil is a heat carrier, so when you're browning the roux with oil, the heat travels further/more evenly and browns all the flour granules to the same color. When you toast dry flour, regardless of how vigorously you move around the flour or how the final roux looks to the naked eye, if you put it under a microscope, you'll see dark and light granules/uneven cooking. Unevenly browned roux is inferior because the pale granules, besides not adding flavor, will actually mask flavor by adding undextrinized starch to your sauce.