I may have been saved by a simultaneous other problem (with the baud
rate, which I had wrong). One the bad options were removed and the
baud rate set and the reset button pushed at the right time, I got a
successful upload message out of avrdude.
Does this mean I didn't manage to erase the bootloader code? Your comment above that I would probably have to buy or build a bootloader
suggests that since avrdude works now, the erase must not have taken. But I'm not certain of the best way to tell, short of trying -e again with the correct baud rate 
Thx,
Britton