i can't answer your questions about differences between 3puck and 4puck as i myself are still searching for the answers..
i'm not as knowledgeable like any sifu,but i think any given racing clutch will be the hardest..while semi-racing clutch slightly hard..
for me,im opting for semi racing clutch for my daily driving..its because i'm used to it..i know how to control,how much to depress,press the clutch and the accelerator..
currently i'm using a normal clutch.which i really dont like at all..the throttle response is slow..the acceleration is also quite not up to my liking..so i prefer semi-racing clutch..
its a matter of own preferences actually.. =)