Peter,
Do you have a stock master cylinder or aftermarket?
I believe that your clutch actuating arm may be one spline off, it looks as though it should be one more toward the rear. You have taken up all the slave rod adjustment to it's shortest, which should not be the case.
If you remove the helper return spring how much play do you have? If that is more than a couple mm then the first portion of your slave travel is purely taking up slack until the throw out engages on the clutch diaphragm. All you want is for it not to ride on the diaphragm, which is what the stop screw sets.
Happy New Year,
Julian
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