And after about three hours of searching, I found my first ever volcanic site.
Once I actually got into a rhythm, and laid out an actual search pattern starting along the equator, using the glide method, I found this site close to the equator about 3/4 around from where I started. Now, if I had done my SRV circumnavigation along the equator rather than pole to pole, and had managed to stick close to the 0° parallel, I have actually have run across this site as it is only about 500m off the true equator.