If you have carbon wheels and use long presta valves you will be familiar with the problem of valve rattle at higher speeds. No drama - just annoying.
This is an example of how it is simply fixed with a small stabiliser. This is precisely tailored for Bontrager Aeolus 5's - but I suspect that the fine details of curvature don't really matter a whole lot; for most carbon wheels it will probably work perfectly well...
If the fit is not snug enough for you - at least now you have the idea and can go and design your own!
The STL includes a separate flange which just ensures the air moving over the HPB does not lift the item. You can make lots of copies of this STL on your build plate to produce a batch. You will probably get better quality the more you print, since it will give more time for each layer on a given stabiliser to cool. With small parts the layer print time can be so quick that the print remains plastic and deforms during the printing process. With more time to cool, each item will be dimensionally more accurate.
This is an incredibly simple bike tweak that works perfectly - without adding more than a gram or two to the bike. (Daft issue I know - but some people worry about these things ;-) )