Do you have any Happs joysticks around? I would be very surprised if you couldn't just take Happs' switches and pop them on the T-Stick. If you can, try one, and if it works you can order just the switches from Happs by getting the specific part number off of the exploded view drawings.
I'd love to hear that this works!
My guess is the clicking noise might go away, but the stiffness is in the springing of the stick itself.