As have many of us, I have settled on the R7(A) and 515 as
two of my keepers. The 515 is extraordinarily sensitive and
I believe even more than the R7A. But the R7 has so many
tuning options, including the amazing Passband, notch and
selectivity options, that it makes DXing a breeze. I have
never minded the ergonomics of the R7 that much. The addition
of a RV75, which has become one of the rarest items on
Ebay, improves thing a lot with the R7.

Would be interest in finding out from other 515 owners if anyone
has located the master oscillator adjustment pot (if there is
one) as I would like to bring my 515 smack on frequency.