Patto, when tightening the screw, add a little thread lock and use the brake lever to hold the shaft when you tighten the screw. I haven't had mine come loose yet.
Shano, glue the bladders to the eyelets making sure they are completely sealed. You can use the bladder from an MTX if needs be but it needs to be trimmed. Just use anything other than the original black bladder that turns as hard as a rock. The later orange and blue ones from TM were quite good if you got a later kit.
Kodak, You got some extra washers in your kit that are perfect for using in between the black plate and the swaybar mount and between the arm and the bulkhead to prevent the rubbing you are seeing. The washers are in the clutch washer bag. They are the very small ones (usually used for extending the length of the front collar on certain motors.