Thanks for sharing! I did see that one just after my post. Helpful to hear you've had a good experience with it. I have a. Electronic groupset so I assume I can just find some 5mm plugs for the unused holes?
I presume you can use some frame gasket plugs. I’d still adequately grease the bearings just to prevent any moisture build up.
Also looks like ZTTO has the same headset cover with different size c-rings:
https://www.aliexpress.us/item/3256809101207750.html