Now that I have a Fanatec DD2 it seems like some cars should be easy to drive and some should be heavy. What I'm getting is that almost all the cars feel similar in weight. Am I wrong? What car should have the heaviest steering and what car should have the lightest?
The default ffb multipliers are most likely set so that all cars feel right on lower end wheels. Typically older cars (no power steering) and high downforce cars would have a heavier steering feel. I'm not sure if the default values change depending on what wheel you have plugged in, you may find that when the proper podium profile is added that they change. (Or maybe not).
I was hoping there would be a way to let the sim tell me what the differences should be as opposed to me setting the values myself.
Well, it does save the FFB multiplier per car, which means you can just tweak it to your preference and then it's done. Don't need to touch it again for that car. To be honest that's better than forcing particular settings on you, and making you adjust your actual FFB settings if you don't like how a car feels.