There are several pickup points on my "aftermarket" non-VW throttle pedal. I attached the cable at the closest one to the hinge point, which seems to work with the comparatively longer attachment at the throttle arm on the hexbar.
But what I'm telling Mike about, and you, Gordon, is rotating the throttle arm by one or two flats on the hexbar, but probably only one flat. This will give you a "cam" action, less movement initially around the "just open" part but as the throttle opens the arm will be more perpendicular to the hexbar. Then it will get to full quickly.
I believe a lot of pan cars are sensitive to throttle because they need a bow in the throttle cable housing, just like the clutch "Bowden tube" needs.