I modified my driver's side seat rail yesterday. I had the seat all the way back and still felt too close to the steering wheel. Part of the issue is the adapter for my Nardi wheel, which puts the wheel back a couple inches further than a stock wheel. In top of that, I'm 6'-1" and have long arms.
What I did was added three screws to the rail that would act like additional tabs for the seat to latch onto. I spaced them the same as the two factory tabs, 20 mm. On the picture below, you can see the two stock tabs toward the left of the rail, and the three #12-24 screws I added rearward with the same spacing. Those three screws will allow me to move the seat back up to an additional 60 mm (~2.36") back further than the factory arrangement.

Here's the seat latched to the screws. The position it is there felt good at least just siting in the car, we'll see how it is when I drive it. I can go back another0.8" or 1.6" from this position if needed, but I think this position is going to be the best balance between my arms to the steering wheel and my feet to the pedals.
