[Cal MX5]

I have recently purchased a car with a 901 box and have the exact same issue. I have replaced the coupler bush and also the 2 bushes in the gear lever. I have played around with the adjustment of the coupler clamp, but am still not convinced I have it right. Yesterday I purchased some Swepco 201, as the previous owner couldn't tell when when the gear oil was last changed.

One question re the adjustment, what effect does moving the rod coupler clamp fore and aft have? I have only been adjusting it's rotation.