I agree on using the RF gain also. There is little to gain by pumping extra noise into your ears.
In fact, on some of the newer QRP rigs with SDR or SDR-IFs reducing the noise into the ADC
seems to make an improvement in the effectiveness of the digital algorithms.
I do quite a bit of QRP on 160M and in contests like the recent Stew Perry distance challenge
you need to ride the RF gain with all of those huge signals flying about. I had a lot of fun
as a QRP entry in that one again this year with my Argonaut 6.
Carl - WB0CFF