Wico 4-way vs 8-way leaf joysticks

[sdrob04]

I've been able to locate a few NOS 4-way Wico joysticks but have had no luck finding the 8-ways.  My understanding is that the 8-ways have two distinctions--a different diameter switch actuator at the base of the stick and a different size/shape of opening in the upper joystick assembly itself (the part that limits stick movement.)

Assuming I can locate (or machine) a new switch actuator, can I simply round out the normally diamond-shaped molded washer in the joystick assembly to the shape and diameter of an 8-way?  Not having seen one up close, I have no idea of the shape or dimensions of the opening on an 8-way.  Has anyone tried to do this?  I don't want to ruin an otherwise perfect joystick if it's too risky.