Well as you may know hydraulic clutches  are self adjusting.  As the clutch plate wears out and gets thinner more fluid from the master cylinder enters the line to take up the slack.  This is the same principal used by modern hydraulic brake systems. With hydraulic brakes the peddle feels the same with new brakes as it does with brakes close their service limits. One thing that can be done however is to lengthen and shorten the push rod that goes between the clutch slave cylinder and the clutch fork.  This  can slightly change the clutch engagement and disengagement point as well as the total throw of the clutch. That is the theory anyway.  I had my father get to work on his lathe and turn out this little prototype.