Hi !!! I also have a Logitech G27 !!!
My (STM) 0.030 and not 0.35 is too much for me! With the Logitech G27 on the Nordschleife (STM) to a value greater than 0,030, with (vehicle ffb people) all general cars to between 0.65 and 0.75, because if I exceed this value by car there differente there will be abnormal oscilliations my logitech g27 will tense !!!
For me, it is very difficult to remove the dead zone in rfactor 2 with logitech g27. It is a shame because, at this moment I like to ride with the honda nsx who feels weak at the center of logitech g27 and increase (STM) I do not feel the front wheels lose traction.
For me setting the logitech G27 seems right to me. I believe that for the moment there is no better !!