Hi mate,
Ok so I have only ever used buttons for sim racing, and over time I have developed a technique for accelerating and braking. I have never used paddles for progressive acceleration etc, and I probably would not get on with it. I cannot be progressive with the buttons, the only way it works is by carrying as much speed into the apex of the corner as possible. Sometimes I find myself using a higher gear for a corner than people that use pedals, due to the fact that, if I went down one more gear, my buttons will stop the car too much which makes me lose time.
Single seater cars are very tough because of the downforce and the fact that progressive throttle is what makes you quick in a single seater, but with a touring car or anything that is closed-wheel, it is all down to the technique with the buttons, traction, braking late etc.
If you look at the Thrustmaster F1 Wheel, I use the DRS (yellow) button to accelerate and the K (green) button to brake.
I use pedals in the clio, I just have adapted Pedals and a hand clutch on the steering wheel
Hope this helps