Yes, I tried it. I actually made a longer push lever, and it did make a difference. My problem was that I found the clutch hard work in traffic/up and down the box as I found it heavy to operate. A problem not mentioned on the post is that you will also have to modify the cable support bracket (the chrome one in the picture) as the longer arm alters the angle at which the cabel passes through the hole. Excess wear may result if you dont. Grahamm still has mine, he tried it a while ago, I lent him both parts, he may wish to lend them onto you for a cheap trial.
However, I cant praise the Magura hydraulic clutch unit I fitted a couple of years ago enough. Its been brilliant, light as feather, consistent take up, and easy to install. Not cheap, but a great piece of kit