First thing, Danowat, uncheck "combined pedals" in the windows options and select "separate" for throttle/brake axes in LFS. This way, you can use them at the same time to balance the car, or whatever. Now you have it so they work as a single axis, y for example, and can only do one at a time.
Second, someone else chime in on how to set up the DFP for 900 degrees. I don't have a DFP. You can either set the windows options up to match the car you are using, ie, racecars have smaller rotation than roadcars. Then set wheel turn to the same in LFS. Or, this is where others chime in as I'm not sure, you can set both at 900 degrees and use "wheel turn compensation" to have it automatically set to the rotation the car uses.
Next, I like the overall strength in windows and force strength in LFS you are using. I use similar, 60 in windows actually and adjust LFS 35-50 depending on car. I use 50 for FWD and the lower for RWD.
Windows spring effects strength. I go off the wall compared to the majority here and have mine set at 138% (is this the thread I explained a while ago this?
). Anyways, in RWD, I always had the feeling of the FF being lagged behind when the back end would break loose. I couldn't catch and countersteer at all. Someone back at RSC claimed the same feeling and found setting the spring effects strength high (above 100%) fixes this. I found that to be true and have been using it that way for months now. The majority may disagree, but some back then agreed and it fixed it for them and I've had some tell me it helped when I suggested it to them as well. The majority will say it should be set at 0%. Try it both ways and see for yourself.
Damper effects strength should be set at 0% period.
Centering spring (this simulates having a spring in the wheel to return it to center automatically like a non-force feedback wheel) should be UNCHECKED and set at 0%.
In LFS, I see you have "throttle and brake centre reduction" set at 25% (0.25). This should be set at 0.00.
One final thing. You don't show it in the pic, but click on "Axes/FF" where you assign the throttle, brake, and steering. At the bottom you should see "remove deadzones". Make sure you select "yes" for that. If not, you will have a deadzone and it will make the steering real goofy when you are trying to keep it going straight.
Hope that helps out. I'm sure as I type this and stop often to yell at the kids fighting, someone else probably beat me to it.