Think about this carefully. There's a reason why VPI no longer puts covers on their turntable motors. Check out the new classic, for instance, the modern-day "replacement" for the HW-19.
Pierre Sprey (Mapleshade) visited me one evening and was appalled that I was using the motor cover that came with my VPI TNT Mk. II. He demonstrated just how much it was muddying the sound by removing it and then replacing it. Said that the same thing applied to the HW-19 (I had a Mk. III earlier). I believe he called these motor covers "resonance sinks," but whatever you call them they do a number on the sonics if your system is resolving enough. Dave