Which tubes for the Audeze LCD 2 with Lyr?

I am looking to upgrade my Matsush*ta 6922 tubes in my Lyr for something than can really bring out my LCD2's. I have researched and it seems the tubes that everyone loves is the Siemens E88CC with grey shields. They're hard to find but worth it I guess. My budget is $200 but I am willing to stretch it to $250 if the pair of tubes are worth it. ALSO, if anyone here are wanting to sell/trade tubes then PM me. Thanks.