Well, i tested (for 1.5 hours) the min FFB torque value using the default 60% overall effects strength in the t500 control panel and 0.8 ingame ffb multi for the megane at Mills Metro to avoid ffb clipping.
I really like it. It resolves the weakness of (or should i say non-existent) low end forces that occur during turn ins and exits of corners. Where the wheel would get loose and you'd be left sort of flapping the wheel about trying to find/judge grip, balance and confidence in the car.....no more. Solid consistency improvement through-out an entire corner (especially the slow ones!), from turn in to exit.

This meant i was more than happy to keep on the power (rather than having to coast) during these situations and i was continuously receiving information through the ffb about the car's balance. Just excellent! Thank you for adding this Terence/Dev's!
There was only one negative which you predicted perfectly Terence, that is the oscillation around the wheel's equilibrium position (however it wasn't aggressive or dynamically unstable but a little annoying none the less) . In the corners, so long as i didn't change the car's balance aggressively (which is a no-no anyway) the ffb force at the wheel kept to one side from turn in to exit. This meant it didn't cross over that discontinuous point (at 0% ffb force ingame) producing a sudden change from +8% to -8% torque at the wheel. Only when driving aggressively with counter steer required (causing the ffb to flip direction in the corner) or driving down a straight could i feel the slight bump/jump change from +/-8% force at the wheel.
I think there are two main reasons for the problem. The first reason is that the deadzone amount i've calculated for my wheel (the same used for testing other wheels) measured only the forces required to overcome the static friction and not the rolling friction. Which is why when i used 8% min FFB torque, it would not oscillate if i put the wheel in a position that started from static but if i gave it a slight nudge, it was enough to then overcome the static friction and the wheel would oscillate intermittently on it's own. It's not an issue in the corners but can be felt on the straights.
The second reason is that the new response curve from adding a min ffb torque (whilst very good) is still a linear approximation. In reality the ffb wheel is producing an initial non-linear slope (in the dead zone region) that then turns into a linear line. So, i've added a little more to the equation to account for the initial non-linear slope.
Maybe this could smooth out or completely remove the slight oscillations around the 0% ffb torque?