I know Chunce doesn't need the springs anymore, but just to clear up the confusion:
Kowal: Wico leafswitch joysticks don't use a main spring like the one in the P360 for handle resistance. They use a rubber grommet, similar to the one one an original PacMan stick. They do use a little tiny spring to keep downward pressure on the actuator- this spring is not available from Happ. Wico microswitch joysticks do use a main spring; a P360 spring might make a good replacement for that one.
Anyone who's looking for them: Replacement actuators and small springs, along with balltop handles and rubber grommets can all be purchased from Ponyboy in the Buy/Sell/Trade forum.