1. I use a 440 as well, and I put the turning angle down in Options > Controllers, but I recently found that in the car setup it helps to put the controller steering setting (I can't remember what it's called or where it is) down to match as well. I never noticed it before
My biggest problem with that wheel is trying to go in a straight line
2. Is your spinning problem with all cars or just RWD? There's only 2 things usually cause me to spin out at corners in the RWDs. The first is too much power (as you'd expect), and the other is brake balance set too far to the rear. I wouldn't think that 10% power would be enough to cause a spin though.
3. The Inferno setups are designed for specific drivers to do one really fast lap. A lot of them aren't any use for actual races at all. I rarely ever touch them because I prefer to get my car handling well for my style, rather than changing my style to suit the setup.
Besides, being such a new licensee, it's not really surprising you can't keep up with people who have done 50,000 miles