Well darn aluminum would be better for heat dissipation, I wish Alaskans hosts would come in, I really want to do a 7A75 with a 4X C-lens pair and 3XBE, I have scored several NOS ndb7a75's and a couple of ndg7475's on ebay, it seems everyone spent their tax refunds or they are paying taxes now and they are all broke because NEW NDG7475's were auctioning for 70 dollars and change, but now they have stopped putting them on the auction block.
Funny even my local Chinese restaurant says things always get slow at tax time, I suspect the refund people spent out and us self employed are all paying.