Oh, I see, nice paint drawing 
The coupling design itself is a little bit tricky to get it right. You will have a lots of trouble with mechanical dead zone, because of too complicated lever system (red bars in drawing). Make sure, when you plan lever system, to make the same lenght (L) of lever on the pot and the distance between mounting point on pedal rod and hindge axis, as indicated on figure below. That way you'll have 1:1 linear pedal angle translation. Lenght (d) is entirely up to you, as it doesn't change anything.
The coupling design itself is a little bit tricky to get it right. You will have a lots of trouble with mechanical dead zone, because of too complicated lever system (red bars in drawing). Make sure, when you plan lever system, to make the same lenght (L) of lever on the pot and the distance between mounting point on pedal rod and hindge axis, as indicated on figure below. That way you'll have 1:1 linear pedal angle translation. Lenght (d) is entirely up to you, as it doesn't change anything.
AA™| rane