Oli,

This is interesting, that is using 3D printing to make a switch cover. I like the idea. I know a few people that simply use fuel line for gas engines and cut it short and then slip in on the switch near the top. It helps. I think with your technique, I'd like to see a cluster or series of bumps (dots) along the length of the switch near the top. You could also use "file grating" similar to what is on the control sticks in your photos. Having such a large feature on the top such as the turbine and ball is over kill. A more elegant solution would be to start small with the sleeve at the base and then tapper it out awards the top and incorporate file features or bumps on the side of the switch near the top. What kind of machine did you use to print the switch covers?

Ken