How did the '57 D-getter work out for you? I recently received a '50s Westinghouse 6SN7GT Reliatron that I was looking forward to trying out, but I noticed one of the heater filaments being more dimly lit than the other one and sure enough one channel was out ($7 and supposedly tested well). I also had bad luck with a NOS NIB 1942 RCA gray glass 6SN7GT that I found for $8 (the cheapest one I bought before was ~$20). As for the 1960's Westinghouse 6SN7GTBs that I bought for pretty cheap, they have quite a massive soundstage like you mentioned earlier. However, they are a little dry sounding when paired with a '50s RCA 6AS7 black plates. I remember feeling that they sounded better paired with the Tung-Sol 7236, but it has been a few weeks since I last listened to that pairing.