Does your headlight is now perfectly seald, INCLUDING the breather hole? Congrats, you'll never get it fogless...
The only need of thet cover is not to make water come on the built-in high voltage transformer of the "native" 9500 lamp. The lamp itself is perfectly sealed, it has a rubber ring around the mounting plate, like in gen1, where there is no such cover and nobody has any fogging problems. From the other side, your "handmade" rings does not has any sealing, and now you have a problem to make this plastic cover perfectly sealed, what has nothing to do with it's factory construction, and can not be so easily made...
(there is another issue with that placing of aftermarket lamps - no one of the lamps, 9005/9006 at first, does not fit correctly, the burning arc is not the same place as factory one, so what the light have you got?)
My opinion as that we must not try to be smarter then the atomotive engineeres that made our Marks, try to understand the idea, and make something alike.
PS The only bulb to place the arc in place can be D2S/D2R, according to dimensions from
www.donsbulbs.com .