I don't get critical very often but I do have to chime in on this one. Nothing personal, I'm just a disappointed consumer.
I also bought the Hinge Protectors as well as the antenna cover and the A/B button rings. And just as you discovered, the hinge protectors are a poorly made item with a terrible fit up on the antennas. I could only slide mine down less than one half inch before they were so tight I could barely "reverse course" and
pull them off. It was as if the heat produced at the molecular level from the pressure and friction between the two surfaces was bonding them together when forcing the sleeve down the antenna.
If I were to somehow be successful at sliding them all the way down to the hinge without snapping the antenna
I can guarantee you would never be able to remove them. The force it would take pulling them off would rip the antennas right out of the RC body. Mine remain in the shipping bag until I can get out my tiny
jeweler's files and just as you, begin filing down the interior dimensions as well as the outer fit to get them functional. I had considered contacting the maker about this apparent manufacturing flaw but the 'damage' was already done at my end with my purchase. The marketing video is very misleading on attaching the hinge protectors and their performance. And it shows there is no tight fit.
After I re-machine the hinge protectors I will purposely leave them
almost loose (like in the video) and put a drop of hot melt glue on the antennas next to the protector edge as an added precaution. Or use a tiny rubber band or O ring rolled down to the item which should work as a seat belt. As far as the antenna cover, I hold it on with a rubber band when storing the RC in the case for now since I don't have the hinge protectors mounted yet.
The button rings do work. Since attaching them I've not had one accidental press of A or B. But it was a pain trying to cut out the center of the two sided tape for a clean smooth edge. I had to use tiny scissors I use to tie fishing flies in order to access the interior of the ring. Perhaps cuticle scissors would also work if your significant other has a manicure kit. A single edge razor blade just don't cut it.