In the end, 10m WSPR sprang to life later in the day, but only Gs seen on 6m WSPR. This was not the great Es opening I was (half) hoping for today.
UPDATE 2050z: I think I might QSY from 6m to 630m (472kHz) overnight with my earth-electrode "antenna".
UPDATE 2106z: QSYed from 6m to 630m and did a hard reset of the 10m beacon. Will be on 10m and 630m WSPR overnight. 6m was a dead loss today, so hoping for better luck on 630m despite the lower ERP on MF.