@muzlukarpuz I was using a T500RS until a while ago. I switched to a DD wheel from SimuCube recently. I am not a torque-junkie and have to tone down torque quite a bit due to a lingering wrist pain. Currently using 10.5Nm, which should be slightly more than double what your belt-driven wheel base pushes out. For me that is enough torque to wrestle with. Don't want my hand ripped off either.
It doesn't sound that much of a change, but I can tell you it is day and night.
What my T500 could
never do is
- keep proper levels of holding forces when e.g. cornering,
- bring out small FFB details due to obviously low responsiveness of the belt/motor (road effects, under/oversteer,...)
Mostly these two things were nagging me since trying a DD wheel for the first time. For me there was no turning back. Not sure I read your problems correctly, but there might not be a cure for the settings on your T300 if you have high hopes.
What
@maelstrom explained were roughly also my settings with my old T500. IIRC I had 85%-90% gain (all gain settings 100% in TM software), 15%-20% road effects, 100% damping. minimum force 2%.