4. Turbo & Pole Position can't be helped very much. They used no limits, spinner-like, wheels. Since the DFpro has limits, even if at 900 degrees, mame treats the input as digital, with a deadzone and a single "turning speed" once the wheel gets out of the deadzone. You can change the deadzone with mame's -joystick_deadzone setting in mame.ini (or a game specific ini), and the turning speed with mame's analog digital speed setting in mame's analog controls menu. Spy Hunter, OTOH, should work fine, once setup correctly. Make sure the wheel is mapped to paddle analog in mame's input menu, and NOT mapped to "paddle inc" or "paddle dec". (The latter two are used for converting digital input to analog, even with analog inputs, after mame translates to digital) Then decrease the deadzone close to zero (the default is 0.3, or 30%, the DFpro probably wants something between 0.0 to 0.02), and you should be good to go.
As a general rule, if you have any half decent analog controller, and are playing an absolute analog game (analog joy, paddle, 270 wheel, or lightgun) set the deadzone to close to zero (0.0 to 0.05).